Onions are one of the world’s oldest cultivated plants, and it’s easy to see why their popularity has endured. Valued not only for their flavor but also for their ease of cultivation and long storage life, onions are grown widely for both commercial production and home gardens. Indeed, they make for an excellent home-garden crop because they are hardy, versatile, and provide a reliable yield with relatively modest care.

The common onion is thought to have originated in southwestern and central Asia, and today comes in a variety of forms, mainly cultivated for their enlarged bulbs. These include the globe-shaped white, yellow, and red onions, the large mild varieties such as Spanish or Bermuda onions, and smaller types like pearl onions. Some forms, including green onions (also called scallions), are grown mainly for their flavorful leaves.

Growing onions is generally straightforward. They grow well from seed, transplants, or small “sets,” and don’t require highly specialized care. Considering their low maintenance, easy harvest, and usefulness in the kitchen, onions of any sort are a must if you are starting a vegetable garden.

Quick Onion Facts

What is an Onion?

Onions (Allium cepa) are part of the Allium family and are closely related to garlic and chives. They are fascinating plants that grow in layers, all wrapped in a dry, papery skin. Each layer corresponds to one of the onion's hollow, tubular leaves above ground. So, the more leaves you see emerging from the top of the plant, the more layers of crunchy onion there are underneath. If you see lots of leaves, you can bet you're growing some big onions.

Even though we usually grow onions as annuals, they are naturally biennial plants. In their first year, they focus on producing leaves and building up the bulb. If left in the ground over winter, the following spring the plant sends up a tall flowering stalk topped with a round cluster of small white flowers, which then produce seed.

Types of Onions

As alluded to above, there are various types of onions that can be useful in the kitchen when harvested at just about any stage:

• Yellow onions: These are the most widely used cooking onions. With a strong, balanced flavor that mellows and sweetens when cooked, they store very well in a cool pantry.
• White onions: Milder and sharper than yellow onions, white onions have a clean, bright flavor.
• Red onions: With purple-red skins and crisp texture, red onions are mild enough to eat raw, so they are popular in salads, sandwiches, and pickles.
• Sweet onions: Also known as Vidalia, Walla Walla, and Texas Sweet onions, sweet onions have a lower sulfur content, which gives them a mild, sweet flavor. The one drawback is that they don’t store as long as yellow onions.
• Pearl onions: These tiny, white onions have a mild flavor and so are often used whole in roasts, stews and pickled recipes.
• Green onions, also known as scallions: Harvested before the bulb forms, scallions have tender white stems and mild green tops. They add an oniony brightness to dishes when used fresh or cooked.
• Similarly to green onions, bunching onions and spring onions are onions that are harvested prior to their bulbs enlarging. They are valued for their flavorful, slender stems rather than an enlarged bulb.
• Shallots are closely related to onions and have a mild, slightly sweet flavor that works especially well in sauces, dressings, and refined recipes; if you’re interested in growing shallots, they’re easy to cultivate and well suited to home gardens.

Burpee offers several dozen varieties of both bulb and green onions as seeds and sets. For either, you can harvest by digging up the whole plant or just clipping off a portion of the green stems. In the latter case, the plant remains growing and can produce multiple harvests.

Short-Day or Long-Day Onions?

One key factor in growing a bountiful crop of onions is knowing the day length requirements of the particular variety you are growing. Onion bulb formation is dependent on day length, or more accurately, the number of hours of daylight the onions receive, and this is determined by genetics. Short-day onions will produce a bulb when days have about 10–12 hours of daylight. These onions would be suitable for southern gardens with mild winters. Examples of short-day varieties include Texas 1015 SuperSweet, Red Creole, and White Bermuda.

Long-day onions need 14–16 hours of daylight to begin forming a bulb. These are ideal for northern climates with long summer days. Examples include Walla Walla, Yellow Sweet Spanish, and Redwing.

A third class of onions—day-neutral or intermediate-day onions—form bulbs at around 12–14 hours of daylight and work well in many mid-latitude gardens. Planting the correct type for your region is essential. If choosing the wrong day-length variety, the plants may never form bulbs or may bolt prematurely. These intermediate-day onions include Candy, Super Star and Red Candy Apple.

Planting Onions

Whichever type you grow, onions are a relatively low-effort yet rewarding experience. The first step is to decide whether you want to grow them from sets, seeds, or transplants.

Sets, Seeds or Transplants?

An onion set is an immature onion bulb grown the previous season and dried for replanting. This gives gardeners a quick and reliable way to produce full-sized onions the next season. Sets are popular because they establish easily in cool soil, resist pests better than seed, and significantly shorten the time to harvest. When purchasing, look for firm, dry bulbs about the size of a marble. Choose uniform sets matched to your day-length region (short-day, long-day, or day-neutral).

Onions grown from seeds take longer than other methods. Especially if your area has a shorter growing season, you'll need to start by sowing seeds indoors and transplanting seedlings later to the garden.

Transplants are onion seedlings that you can either purchase from a garden center or online, or can grow yourself from seeds sown indoors.

When to Plant Onions

If growing onions from seeds, sow the seeds indoors 8 to 12 weeks before the last frost in your area.

Onion sets can be planted in the ground once the soil temperatures rise to around 50°F (10°C).

If going the onion transplant route, wait until the last frost date for your location has passed. Remember to harden off seedlings before moving them out into the garden, then transplant the onions to their beds.

Best Soil for Onions

The best soil type for growing onions is one that is sandy-loam or silty-loam and is rich in organic matter, well-drained, and has a soil pH between 6.0 and 6.8. This 4-in-1 soil moisture meter from Amazon also measures soil pH, temperature, and light levels.

If your soil is heavy with clay, amend it with a rich compost.

Onion Light Requirements

Onions at a minimum need at least 6-8 hours of sun on a daily basis for bulb development. However, as we noted above, the specific amount of daylight (day-length) for bulb formation depends on the variety. In very hot climates, a bit of afternoon shade could be beneficial.

How to Plant Onion Sets

The method for planting varies depending on if starting from seeds, sets or transplants. The most common method is to plant onion sets directly into the garden:

1. Prepare garden bed: Ensure you have loose, well-draining soil at a pH between 6.0–6.8. Add in compost to loosen soil if necessary.
2. Planting spacing and depth: Break apart onion sets into individual bulbs and space about 4–6 inches (10–15 cm) apart in rows 12–18 inches (30–45 cm) apart. Push onion sets so the top is just a little below soil surface (about 1 inch / 2–3 cm). If using transplants or seedlings, separate into single plants and follow the same spacing.
3. Water and mulch: Water in well to settle soil and eliminate air pockets; apply a light mulch to conserve moisture and suppress weeds.

Growing Onions from Seed

Onion seeds are typically started indoors 8 to 12 weeks before the last frost:

1. Seed mix and trays: Use a lightweight seed-starting mix and shallow flats or cells. Sow thinly. This Burpee 36-Cell Self-Watering Greenhouse Kit from Home Depot creates just the right environment for germinating onion seeds.
2. Sowing depth: Cover seeds lightly (1/8 inches / 3 mm) with the seed starting mix. Keep soil moist but not soggy.
3. Light and temperature: Place the tray under grow lights or a bright window; keep the soil temperature between 65–75°F (18–24°C).
4. Thin: When seedlings reach 2–3 inches (5–8 cm), thin seedlings so plants are 1–2 inches (2.5–5 cm) apart (you’ll pot up or transplant later).
5. Pot up: Move these seedlings to larger pots when about the thickness of a pencil to avoid root crowding.
6. Harden off: Gradually acclimate seedlings to outdoor conditions for 7–10 days before transplanting, then proceed as directed above.

Thinning Onions

Crowded onion plants won’t form full bulbs, so thinning is critical. Once seedlings reach about 3–4 inches (7.5–10 cm) tall, pluck out seedlings so that the remaining plants are about 2 inches (5 cm) apart at first. As they grow thicker, thin again to a final spacing of 4–6 inches (10–15 cm) for standard bulbs (or wider for larger types).

Always snip or gently pull the smallest or weakest plants, leaving the strongest to grow. Thinning is easiest when the soil is moist, which helps avoid disturbing nearby roots. Proper spacing from early on gives the remaining onions room to swell into full, uniform bulbs.

The good news is this: anything you pluck out is edible! Use the tiny onion greens like chives or scallions.

Onion Plant Care

Onions are an easy, rewarding crop, but they still benefit from a little regular care. They don’t need constant attention, but a few well-timed jobs will help them grow strong and healthy. Water during dry spells, feed to support steady growth, and keep on top of weeds and pests to give your onions the best chance of producing good-sized bulbs.

How Often to Water Onions

Watering onions well is necessary for growing a successful onion crop. They need a lot of water and should be constantly moist, but the soil should never get soggy. Ideal onion water needs are to irrigate to a depth of an inch (2.5 cm) once a week rather than a light sprinkling each day. When the tops begin to die back, cut back on the amount of watering to prevent the tops from rotting.

If you are watering onions with a hose or sprinkler, water in the morning rather than during the heat of the day, which will just end up evaporating.

Other than using a hose or sprinkler, onions can be watered by furrow irrigation or drip irrigation. With furrow irrigation, furrows are dug along the length of the onion row and flooded with water. This allows the plants to slowly soak up the water. Drip irrigation involves the use of a drip tape, which is a length of tube tape with punched holes that deliver water directly to the roots of the plants. This method for watering onions eliminates the issue of fungal disease that can result from overhead watering. This Treela Drip Tape from Amazon is a good option.

To tell if the plants have enough water, stick your finger in the ground next to the plants. If you can’t feel any moisture up to your first knuckle, it’s onion watering time.

Fertilizing Onions

Onions are heavy feeders, so they grow best in soil enriched with a few inches of compost before planting. During the early growing phase, they benefit from a regular nitrogen application, such as fish emulsion, blood meal, or a balanced fertilizer every two to three weeks. This builds strong leaf growth that then leads to larger bulbs. This Gardenwise slow-release 10-10-10 plant fertilizer, available from Amazon, is a good choice.

When the plants reach about 4–6 inches (10–15 cm) tall, side-dress with a nitrogen-heavy fertilizer along the rows and water it in, repeating as needed if your soil is poor. Once the bulbs begin to swell, stop adding nitrogen, because late feeding can cause soft bulbs that don’t store well. Keeping the soil evenly moist but not wet throughout the season also helps nutrients move efficiently and supports steady, healthy growth.

Mulching Onions

Mulching onions is helpful but optional, depending on your conditions. A light mulch can suppress weeds, conserve moisture, and keep soil temperatures more even. This is especially useful because onions have shallow roots and don’t compete well with weeds. It’s important that the layer of mulch be kept to a minimum 1-2 inches (2.5–5 cm) to prevent the mulch from hampering the bulbs’ development and trapping too much moisture, which can encourage rot. In cool, wet climates, skip mulch to keep the soil drier.

Harvesting Onions

Onions are a versatile, long-lasting crop that can be harvested in stages. Green tops can be clipped once they reach around 6 inches (15 cm) tall, and the plants will continue to grow, with flavor intensifying the longer you wait to harvest the bulbs. Any onions that have bolted should be used immediately, as they won’t store well.

Once tops begin to yellow and fall naturally, some gardeners gently fold down onion tops to encourage final ripening before harvest, especially for onions intended for storage.

For a full harvest, onions are ready when their tops naturally fall over and brown, usually 100–120 days after planting. Harvest onions early in the morning, when temperatures are cooler, carefully pulling or digging up the bulbs with the tops intact to avoid bruising, which can lead to rot. Shake off excess soil gently using a soft brush or gloved hand, and avoid washing the onions until you’re ready to cure or store them.

Onion Care Calendar

Curing and Storing Onions

After harvesting onions, dry and cure them for 2–3 weeks in a clean, well-ventilated area until the tops and necks are fully dry and the skins are papery. Once cured, trim the tops to about 1 inch (2.5 cm) above the bulb and store onions in a basket, crate, or mesh bag in a dark, dry place at 32–40°F (0–4°C) with 65–70% humidity. These Ahyuan Hanging Mesh Storage Bags from Amazon allow for air circulation during storage.

Properly cured and stored onions can last up to three months, while damp conditions can lead to rot.

Propagating Onions

The most common method of propagating onions is from seed. It’s possible to save onion seeds from plants grown in a home garden, but they might not necessarily produce exact replicas of the original onion plant.

Bunching onions, or Welsh onions, can be propagated by division, or separating individual plants from the clumps and replanting them. Other onions, such as the Egyptian walking onion, form topsets or bulbils at the top of the plant. These can be removed from the plant and replanted to produce new plants.

Overwintering Onions

With the right varieties, planting time, and a little winter protection, overwintering onions can be successful in a wide range of regions and reward gardeners with earlier harvests in spring.

“Winter onions” is a general term used for certain cold-hardy varieties that can be planted in the fall and left to overwinter outdoors. This includes multiplier onions (also known as potato or ground onions), as well as some short-day and day-neutral varieties with greater cold tolerance. These onions resume growth early in spring, producing fresh green tops and, in many cases, earlier bulb harvests. They are commonly grown in USDA zones 4–9, though winter conditions vary widely even within this range.

As winter temperatures drop or fluctuate, some level of frost protection for onions becomes increasingly important, even for cold-hardy varieties. Onions tolerate light freezes, but prolonged cold or repeated freeze–thaw cycles can damage the foliage or even cause bulbs to rot. Mulching, ensuring good drainage, and using row covers during cold snaps can help fall-planted onions overwinter successfully across many climates.

Onion Problems

Home gardeners may run into a few onion-growing problems, though thankfully not all at the same time. Below are some of the more common issues to be aware of:

• Onion bolting happens when plants are stressed by cold snaps or sudden temperature changes, causing them to flower early and stop putting energy into bulb growth.
• Onions that don’t form bulbs are usually the result of choosing the wrong variety or improper growing conditions.
• Weeds can outcompete onions and their shallow roots for vital soil resources.
• Variegated or streaked onion leaves are usually the result of a genetic disorder known as chimera, which affects leaf coloring but does not make the onions inedible.

Onion Diseases

There are many potential onion diseases to look out, some common and others less so:

• Tip blight causes onion leaf tips to brown and die back, reducing plant vigor.
• Powdery mildew causes white, powdery growth on onion leaves and can weaken plants in warm, dry weather.
• Downy mildew thrives in cool, damp conditions and causes pale, fuzzy patches, eventually leading to leaf collapse.
• Allium rust causes yellow to orange spotting on onion foliage and can stunt bulb growth, particularly in wet weather.
• Leaf diseases such as Botrytis leaf blight, purple blotch, Stemphylium blight, and Xanthomonas bacterial blight can cause spotting, lesions, dieback, and reduced yields in cool, wet conditions.
• Root and bulb diseases, such as pink root, Pythium root rot, and Fusarium basal plate rot, can cause yellowing leaves, reduced bulb size, and crop losses, particularly in warm or poorly drained soils.
• Storage diseases, including neck rot, soft rot, mushy rot, and black mold, can develop if onions are poorly cured or damaged during harvest.

Onion Pests

While onions aren't among the most prone to vegetable garden pests, there are a few to keep an eye on:

• Onion thrips feed on leaves and cause silvery streaking and stunted bulbs, as well as tops curling up.
• Onion maggots tunnel into bulbs, leading to rot and collapse.
• Cutworms sever young seedlings at the soil line, especially when plants are just a few inches tall.
• Root knot nematodes damage onion roots, leading to poor growth and reduced bulb size.

But don’t let these issues deter you from growing onions! Many can be addressed with proper spacing, careful watering, mulching, and a keen eye on visiting insects.

Growing Onions in Containers

A small home garden is still plenty big enough for growing onions in containers. Green onions or small bulb onions are especially well-suited to containers, but larger storage types can thrive too if given enough space. Ensure you use a wide and deep container with drainage holes, preferably one that is at least 8–12 inches (20–30 cm) deep and 10–12 inches (25–30 cm) wide for each bulb or a cluster of smaller onions. This gives the roots and developing bulbs plenty of room to grow. You can even grow onions vertically in a large bottle with holes cut into the side.

Use a well-draining potting mix with some added compost or organic matter. Container-grown onions need consistent moisture and regular fertilization, since nutrients leach out of containers more quickly than in garden soil.

Growing Onions Indoors

Onions can be grown indoors, though they need the right conditions to thrive—particularly light. They will require bright light, ideally 6–8 hours of direct sunlight per day, or supplemental grow lights if natural light is limited.

Prepare a container as above and plant either seeds, sets, or transplants, knowing the seeds take the longest to reach harvest. Green onions or scallions are easiest indoors, while full-sized storage onions are possible if the container is large enough and lighting is optimal. Harvest stems intermittently and allow the bulbs to continue growing, or allow them to mature fully for bulbs.

Companion Planting Onions

Certain characteristics of onions make them great companion plants. Their strong scent repels common garden pests such as carrot flies, aphids, and cabbage worms. from neighboring vegetables. It’s also widely believed that onions improve the flavor and growth of neighboring plants such as carrots, tomatoes, and brassicas. And they attract beneficial insects, creating a healthier garden ecosystem.

A companion planting of carrots and onions, for instance, will deter the carrot root fly. In turn, the carrots will repel the onion fly from the onions. Aphids pestering strawberries will be turned away by onions’ strong scent, and cabbage loopers, cabbage worms, and flea beetles that love brassicas will be driven away by onions, as well.

Frequently Asked Questions

Onion Growing Essentials

• Great seeds and sets are the beginning of a bountiful harvest. Find dozens of onion varieties at Burpee.
• Soil pH matters for strong onion growth. Make sure your garden’s soil meets the requirements with this 4-in-1 soil moisture meter from Amazon, which also checks pH, temperature, and light levels.
• Starting your onions from seeds? This Burpee 36-Cell Self-Watering Greenhouse Kit at Home Depot creates just the right environment.
• Watering overhead may lead to fungal issues. This Treela Drip Tape from Amazon with nozzles set at a 6-inch spacing, waters just the roots.
• Air circulation is critical when storing onions, and the Ahyuan Hanging Mesh Storage Bags offered by Amazon allows them to breathe easy.

Clipping coupons is a great way to save money at your grocery store, but so is reusing parts of your produce. There are many leftover bits of produce that you can re-grow using just water, but growing grocery store green onions is one of the quickest. Learn how to plant grocery store scallions for a fast, ready supply always at hand without a trip to the grocer.

Can I Plant Grocery Store Green Onions? 

Almost all of us are trying to save money, especially on our food bills. Most of us are also trying to avoid waste. Growing your own produce from the throw-away bits is a winning teamup of the two goals. You may wonder, can I plant grocery store green onions? This is just one of the types of veggies that will produce fresh, usable produce in short order. Regrow store bought scallions and in about a week you will have usable green shoots. 

A few searches online may have led you to sites where they tout re-growing items like the bottoms of a celery or the tops of a carrot. While the carrot will take off and grow leaves, you will never get a useful root, although the cut base does produce little white feeder roots. The celery will, in time, get some leaves and funny little anemic-looking stalks, but they are nothing like a true celery stalk. One thing you can grow, which is much like its supermarket counterpart, is grocery store green onions. Learn how to plant grocery store scallions and reap the benefits of this fast-producing allium.

How to Grow Store Bought Scallions

It is easy to regrow store bought scallions. Once you have used up much of the green part of the onion, keep the white bulbous base with a bit of green still attached. This is the part that can be rooted and will produce new shoots. Place the remaining onion in a glass and fill it with just enough water to cover the white part of the onion. Place the glass in a sunny window and that’s it. There couldn't be simpler instructions on how to plant grocery store scallions. Change the water every few days to prevent rot and bacteria buildup. Then you just have to wait patiently. 

Using Re-grown Scallions

After just a couple of days, you should begin to see new green growth coming out. These slender shoots can be used immediately, but for the health of the plant, it is best to let a few build up before you start harvesting. That allows the plant to collect solar energy for growth. Once you have a few shoots, you can start to use them. Just allow one or two shoots to remain. This little green onion plant in water won't last forever unless you put it in soil. You can cut and harvest a few times before the onion is ready for the compost bin though. This easy-to-grow reuse of onions is a great way to save money and keep from having to race to the store when you need green onions. 

In recent years, the concept of foraging for food has seen a surge in popularity among younger generations choosing to live more natural lifestyles. Whether foragers are looking to save money, or perhaps wish to fulfill a need for a more sustainable kitchen, there is no doubt that venturing out into the wilderness (or your own backyard) can be quite exciting. In many places, wild edibles are all around us. For most, learning how to accurately identify these wild foods greatly changes the way in which they perceive nature. One commonly foraged plant, meadow garlic, may be hiding in plain sight in the front lawn right now. Can you eat meadow garlic weeds? Let’s find out.

About Meadow Garlic Plants

Meadow garlic (Allium canadense), also referred to as wild onion, is a common weedy plant found throughout the Midwest and eastern United States. Forming loose mounds of leaves that somewhat resemble grass, the foliage of these plants is very similar to that of other members of the Allium family which are cultivated in vegetable gardens (such as onions and chives). Perennial in nature, plants first become noticeable in the spring and, left to their own devices, go on to produce flowers in the summer, though many people don’t notice them since they’re often treated as weeds and removed before having a chance to bloom.

Is Wild Garlic Edible?

Found along roadsides, in meadows, and even in ill-managed lawns, these edible wild onions are one of the most commonly found foraged plants. One major key to the identification of this plant is a very noticeable, pungent onion or garlic smell when disturbed. This characteristic is especially important, as many potentially toxic “lookalikes” do exist – such as the death camas, which is extremely toxic to humans. Both the leaves and the bulbs of meadow garlic plants can be used, most often in the springtime. Make certain only to harvest from locations which have not been treated with chemicals. Additionally, be sure to rinse the plants thoroughly. Common uses include its addition in soup recipes and meat-based dishes. Though small quantities of the plant are considered safe to eat, it does contain sulfides. When eaten in larger quantities, these edible wild onions may cause symptoms such as nausea, vomiting, and diarrhea. As with any wild foraged plant, thoughtful research can help make the decision whether a plant is or is not safe to eat. Location specific edible field guides are readily available online. Many local agriculture extensions also offer free foraging classes. When foraging, safety should always be of the highest priority. If there is any doubt whether or not a plant is safe to consume, it best not to do so. Disclaimer: The contents of this article is for educational and gardening purposes only. Before using or ingesting ANY herb or plant for medicinal purposes or otherwise, please consult a physician, medical herbalist or other suitable professional for advice.

If you are thinking that only onions get onion Stemphylium blight, think again. What is Stemphylium blight? It’s a disease caused by the fungus Stemphylium vesicarium that can be a problem when growing onions and many other veggies, including asparagus and leeks. For more information about Stemphylium blight of onions, read on.

What is Stemphylium Blight?

Not everyone knows or has even heard of Stemphylium leaf blight. Exactly what is it? This serious fungal disease attacks onions and other crops. It’s fairly easy to detect onions with Stemphylium blight. The plants develop yellowish, wet lesions on foliage. These lesions grow larger and change color, turning light brown at the center, then dark brown or black as the spores of the pathogen develop. Look for the yellow lesions on the side of the leaves facing the prevailing wind. They are most likely to occur when the weather is very wet and warm.

Stemphylium blight of onions is initially seen in leaf tips and leaves, and the infection usually does not extend into the bulb scales. In addition to onions, this fungal disease attacks:

• Asparagus
• Leeks
• Garlic
• Sunflowers
• Mango
• European pear
• Radishes
• Tomatoes

Preventing Onion Stemphyliuim Blight

You can take efforts to prevent onion Stemphylium blight by following these cultural steps: Remove all plant debris at the end of the growing season. Carefully clean the entire garden bed of foliage and stems.

It also helps to make plant your onion rows following the direction of the prevailing wind. This both limits the amount of time the foliage is wet and encourages good airflow between plants. For the same reasons, it is best to keep plant density down. You are much less likely to have onions with Stemphylium blight if you keep a good distance between plants.

In addition, be sure that the soil where you plant onions offers excellent drainage. If onions with Stemphylium blight have appeared in your garden, it pays to check into blight-resistant selections. In India, VL1 X Arka Kaylan produces high-quality, resistant bulbs. Welsh onion (Allium fistulosum) is also resistant to Stemphylium leaf blight. Ask at your garden store or order blight-resistant strains online.

All kinds of onions, chives, and shallots can be affected by the disease known as onion fusarium basal plate rot. Caused by a fungus that lives in the soil, this common onion disease can be difficult to catch until the bulbs have developed and ruined by rot. When growing onions, the best way to manage fusarium rot is to take steps to prevent it.

What is Onion Basal Plate Rot?

Fusarium basal plate rot in onions is caused by several species of Fusarium fungi. These fungi live in the soil and survive there for a long time. The infection occurs in onions when the fungus is able to get in through wounds, insect damage, or root scars on the bottom of the bulb. Warm soil temperatures favor the infection. Temperatures in the soil between 77 and 90 degrees Fahrenheit (25 to 32 degrees Celsius) are optimal.

The symptoms of onion fusarium basal plate rot underground include rotting of the roots, white mold, and soft, watery decay in the bulb that begins in the basal plate and spreads to the top of the bulb. Aboveground, the mature leaves begin to yellow and die back. Because the leaf symptoms only begin at maturity, by the time you notice the infection, the bulbs have already rotted.

Preventing and Managing Onion Fusarium Rot

Treating onion fusarium rot isn’t really possible, but good management practices can help you prevent the disease or minimize its impact on your onion yield. The fungi that cause fusarium of onion basal plates live long in the soil and tend to accumulate, so a rotation of onion crops is important. The soil is also important and should drain well. A sandy soil in a raised bed is good for drainage.

You can minimize the chances of having fusarium rot in your onions by choosing certified disease-free transplants and varieties that have some resistance to the fungi, like Cortland, Endurance, Infinity, Frontier, Quantum, and Fusario24, among others.

When working in the garden, take care not to wound or damage the bulbs or roots underground, as wounds promote infection. Keep insects under control and provide your plants with adequate nutrients.

An onion with bacterial soft rot is a squishy, brown mess and not something you want to eat. This infection can be managed and even completely avoided with good care and cultural practices, but once you see the signs of it, treatment is not effective.

What is Onion Soft Rot?

Soft rot is a common onion disease caused by several types of bacteria. It most commonly affects onions while they are being stored, but contamination or the damage that leads to contamination often occurs during or around harvest. If you're learning how to grow onions, then keep a lookout, as the disease can cause a lot of destruction and significantly diminish yields.

Bacterial soft rot infections strike already mature onions. The signs of onion soft rot start with softness at the neck of the bulb. As the infection creeps in, the onion will appear water-soaked. Then, one or more scales in the bulb will become soft and brown. If you squeeze an infected bulb, it will emit a watery, smelly substance.

How Onion Bacterial Soft Rot Spreads

Onions become infected with soft rot bacteria through soil, water, and infected plant debris. The infection gets into bulbs through wounds and damage. The infection is most likely to take hold during warm and humid conditions. Any damage to leaves or bulbs can cause the infection to get in, including hail and rain damage, sun damage, freezing, bruising, and cutting the tops of the bulbs during harvesting. Damage while the bulb is still in the ground, and after it has been harvested, can lead to infection. A pest called onion maggot can also spread the disease between plants.

Managing Soft Rot in Onions

Once the disease has set in, there is no treatment that will save a bulb, although it tends to infect just one or two scales. You can prevent infection in several ways though:

• Avoid overwatering your onion plants, especially when it is hot out.
• Make sure your onions are planted in ground that drains well and that you give them space for airflow and to dry out between waterings.
• Avoid damage to the entire plant while the bulb is developing.
• Handle harvested bulbs gently to avoid bruising and other types of damage that can lead to infection during storage.
• Make sure the onion is fully mature before you harvest it; the drier the tops are, the more protected the bulb is from infection.
• If your onions do get damaged, like after a big storm, you can spray the damaged areas with a copper-based spray to protect against infection.

Pythium root rot of onions is a nasty fungal disease that can live in the soil for long periods of time, just waiting to take hold and attack onion plants when conditions are right. Prevention is the best defense, since onion pythium rot is difficult to control once it begins. What to do about this unfortunate onion disease? Read on for tips.

About Pythium Root Rot of Onions

If you're growing onions, then you need to be on the lookout for pythium root rot. It can infect plants any time soil is moist for extended periods, but it tends to be most severe in rainy weather when days are hot, and nights are warm. The fungus also lives on plant debris and in weed roots and may be spread by overirrigation and splashing water. Onion seeds may be killed before germination, or infection may show up a few weeks later.

The disease also appears on other members of the allium family, including leeks and garlic.

Symptoms of Onion Pythium Root Rot

During early phases of the disease, plants with onion pythium rot appear yellow and stunted. They often wilt during the day and recover in the evening. Eventually, water-soaked lesions develop on lower stems and onion bulbs. A watery rot appears on the roots, which may also turn black.

Controlling Pythium Root Rot of Onions

Plant onions in well-drained soil. Consider planting onions in raised beds, which may minimize the impact of the disease. Similarly, consider growing onions in pots filled with commercial potting mix.

Discard infected plants in sealed bags or containers. Never place infected plant matter in compost. Keep the planting area clean and free of plant debris. Control weeds, as pythium rot can live on weed roots.

Don’t use excessive nitrogen-based fertilizer. Nitrogen causes lush, tender growth that is more susceptible to infection.

Fungicides may be effective when applied every two or three weeks, or any time rain continues for more than two days. Look for products registered for use against pythium root rot of onions. Use fungicides only when necessary; the pathogen may become resistant.

Clean shoe soles after walking on infected soil. Clean tools thoroughly after working in infected areas.

Onion neck rot is a serious disease that most commonly affects onions after they have been harvested. The disease makes the onions become mushy and water-soaked, causing damage on its own and also opening up a pathway for a host of other diseases and fungi to enter and break down the onion. Keep reading to learn more about identifying and treating this unfortunate onion disease.

Symptoms of Neck Rot in Onions

Onion neck rot is a disease caused by a particular fungus, Botrytis allii. As well as being a problem when growing onions, this fungus affects other alliums such as garlic, leeks, and scallions. It is often not identified until after harvest, when the onions are either damaged during transportation or not cured properly before storage.

First, the tissue around the neck of the onion (the top, facing the foliage) becomes water-soaked and sunken. The tissue may become yellow, and a gray mold will spread down into the layers of the onion itself. The neck area may dry out, but the flesh of the onion will become mushy and rotted. Black sclerotia (the fungus’ overwintering form) will develop around the neck. The wounds caused by onion botrytis also open the tissue up to infection from any number of other pathogens.

Preventing and Treating Neck Rot in Onions

The best way to prevent onion neck rot after harvest is handling the onions gently to minimize damage and curing them properly. Let half the leaves turn brown before harvesting, allow them to cure in a dry place for six to ten days, then store them until ready for use in a dry environment just above freezing. In the field or garden, plant only disease-free seed. Space plants about one foot (31 cm.) apart and wait three years before planting onions in the same spot. Don’t apply nitrogen fertilizer after the first two months of growth.

Powdery mildew is perhaps the most recognizable fungal disease and the bane of gardeners’ existence all over the world. Powdery mildew can infect thousands of different host plants. In this article, however, we will specifically discuss powdery mildew as an onion disease. Read on to learn how to manage powdery mildew when growing onions.

About Powdery Mildew on Onions

Powdery mildew on onions is a fungal disease caused by the pathogen Leveillula taurica. While the disease commonly called powdery mildew can affect thousands of different plant varieties, there are actually different pathogens that cause the disease in specific plants. Leveillula taurica is a powdery mildew pathogen that specifically infects plants in the Allium family. his can play an important role in selecting the proper fungicides for onion powdery mildew control.

It is always important with fungicides to thoroughly read the label before purchasing and using these products. In this case, you will want to select a fungicide that states it specifically treats Leveillula taurica or onions with powdery mildew. Using products that do not specifically state this may not only be a waste of money, but it could also cause harmful side effects and not be safe for edibles. That being said, symptoms of powdery mildew on onions are pretty much the same as symptoms of any powdery mildew.

The first, often unnoticed, symptom is light green, yellow, or chlorotic-looking spots or mottling on onion foliage. As the disease progresses, these spots can become slightly sunken and turn a white to light gray color. A powdery white substance will form on these lesions and can eventually coat entire leaves or blades. This powdery white coating is the disease’s mycelium, which contains spores. The spores are usually released on to the wind or can spread by rain or overhead watering.

Onion Powdery Mildew Control

Powdery mildew on onions is most prevalent in the hot, dry conditions of summer months that have followed cool, wet spring weather. The disease can overwinter in garden debris or on the soil surface and can be transferred to new plants by splashback of rain or watering. The fungus then enters plants through their microscopic stomata and begins to grow. As summer heats up, the conditions become perfect for spore production, and this is when we generally notice the obvious powdery white symptoms of the disease.

As with any fungal disease, proper sanitation can greatly reduce the spread of powdery mildew on onions. Cleaning up garden debris, sanitizing tools, and deeply tilling garden beds at the beginning of each new planting season are beneficial steps in onion powdery mildew control. It is also important to not overcrowd garden beds.

Preventative fungicides, which contain potassium bicarbonate, or just some kitchen baking soda, can also prevent the spread of Leveillula taurica. While many fungal diseases cannot be treated with fungicides once the disease is present, onion powdery mildew can be treated with certain fungicides. Be sure to read fungicide labels to select one that will treat this condition.

Bacterial blight of onion is a fairly common disease of onion plants – depending on where you live – that can cause minor losses to a complete loss of onion crop, depending on environmental conditions. While mostly seed-borne, onion bacterial blight can be spread by debris and infected volunteer onion plants.

About Xanthomonas Leaf Blight

Onion bacterial blight was first reported in the U.S. in Colorado but has now also been found in Hawaii, Texas, California, and Georgia. It also affects onions in South America, the Caribbean, South Africa, and parts of Asia.

The disease is a bacterial infection caused by Xanthomonas axonopodis. The conditions favorable to an infection include moderately warm temperatures and high moisture or humidity. Plants with leaf wounds are more susceptible to infection.

Outbreaks of the bacterial blight are more likely to occur after a period of wet, humid weather. After a storm is a time when onion plants may be especially susceptible because of the moisture and any wounds in the leaves caused by high winds. Overhead irrigation can also make onion plants vulnerable to infection.

Onions with xanthomonas blight will show signs of the disease on leaves first. You may see white spots and then elongated, yellow streaks. Eventually, entire leaves may turn tan or brown. Older leaves are affected first, and affected leaves ultimately die. You won’t see rot in the bulbs, but they may not develop, and your yield may decrease significantly.

Managing Xanthomonas Blight in Onions

To prevent this infection in the first place, it is important to start with clean seeds. However, once in the garden, onion bacterial blight can spread in other ways. It may survive in debris or in volunteer plants. Pull out and dispose of any volunteers to avoid infecting your other onions and clean up debris at the end of each growing season.

If you have an infection crop up in your onions this year, rotate your garden and put in a vegetable that is not susceptible to xanthomonas before you plant onions in that spot again.

If your onions get damaged after a storm, use a nitrogen fertilizer to promote healthy leaves.

Keep your onions well-spaced to avoid moisture between plants and to allow for airflow.

If you take these steps, you should be able to avoid or manage an onion blight infection. If you choose to, there are copper-based bactericides that can be applied to kill the bacteria causing the infection.

What would many of our favorite foods be without onions? The bulbs are easy to grow in well-draining soil and come in a wide variety of colors and levels of flavor. Unfortunately, onion mushy rot disease is a common problem with these vegetables. What is onion mushy rot? This is primarily a disease of stored onions that occurs post-harvest. It can severely reduce the edibility of the bulbs. Learn how to prevent this common onion disease and save your stored Allium bulbs.

What is Onion Mushy Rot?

Onions are a prevalent ingredient in many recipes. Whether you sauté them, roast, boil, sear, grill or eat them raw, onions add zest and aromatic delight to any dish. Growing onions is pretty easy in well-draining soil with plenty of organic matter.

Harvesting and storing onions properly will help keep the veggies for months. Mushy rot in onions is the Achilles' heel of stored Allium. It will not only rot an infected bulb, but the disease spreads readily in storage situations.

One onion with mushy rot can spoil an entire harvested crop. This is because the disease is caused by a fungus, Rhizopus microsporus. The latter part of the botanical name refers to the numbers of spores produced by this prolific fungus. Bulbs that have some sort of injury to them, which often occurs at harvest, are prey to the introduction of the fungal spores.

Onions that are stored in high humidity and have not been properly cured are most often affected. The excess moisture provides a perfect breeding ground for the fungus, which overwinters in soil. As a root crop, onions are directly exposed to the fungus but do not exhibit signs unless the protective exterior skin is penetrated.

Recognizing an Onion with Mushy Rot

Early infection signs are slipped skin, followed by softening layers. In white or yellow onions, the layers become darker. In purple onions, the color becomes deeply purple-black. Severely affected onions will smell fairly terrible over time. The odor of the onion will be at once pungently oniony but tinged with a sweet, offensive odor. Just opening a bag of onions and smelling the odor can often identify the disease before visual cues.

If just one onion is infected, remove it and then wash all the others carefully. Lay them out to dry thoroughly before bagging or boxing them up again for storage. This should prevent the spread of this very contagious disease.

Preventing Onion Mushy Rot Disease

Crop rotation can be of some benefit as the disease overwinters in soil and can also be harbored in leftover plant debris. Any form of Allium can become infected by the fungal disease, so rotations should avoid any member of the family planted in that area for at least 3 years. Careful handling and harvest are key to preventing mushy rot in onions. Any mechanical injury can introduce the spores to the onion but so can sunscald, freezing and bruising. Cure harvested bulbs in a single layer in a warm, dry location for at least 2 weeks before packing them for storage. Proper curing can reduce moisture content which encourages fungal growth. Store onions in a cool, dry location.

The pathogen that causes onion downy mildew has the evocative name Peronospora destructor, and it truly can destroy your onion crop. In the right conditions, this onion disease spreads quickly, leaving destruction in its path. There are ways to prevent it and manage it if you see the early signs, however.

Downy Mildew of Onion Crops

If you're learning how to grow onions, garlic, chives, or shallots, then you need to be aware they are all susceptible to being infected by the fungus that causes this type of downy mildew. The fungus overwinters in the soil in many locations, which means that it can become endemic in a garden or field, ruining crops year after year. The spores of the fungus spread and cause infection, especially in conditions that are cool, humid, and moist.

Onions with downy mildew have leaves with irregular spots ranging from pale green to yellow to brown in color. The seed stalks may also be affected. Both leaves and stalks may also host the spores of the fungus, which are initially gray and then become violet. Eventually, the leaf tips will die, and the leaves will collapse entirely, with the spores taking over the dead tissue.

The impact on the edible bulb of the onion plant will be reduced size and it will develop a spongy texture. The bulb will not keep for as long as it normally would. Although the downy mildew doesn’t often kill the entire plant, it does reduce yield and results in onions of greatly lessened quality.

Preventing Downy Mildew on Onions

There are several ways you can prevent this disease in your onion and related plants: Use onion varieties that are resistant to downy mildew. Use high-quality bulbs, seeds, and sets to start your garden. These are more likely to be disease-free.

The infection often begins with infected plants and seeds. Space plants adequately to allow for airflow.

Avoid watering plants when they will not have a chance to dry quickly, such as in the evening or in very humid conditions.

Managing Onion Downy Mildew

The only real way to eliminate downy mildew in onion plants is to spray them with a fungicide. Dithiocarbamate fungicides are used for downy mildew on onions. If you do get an infection that takes hold in your garden, try crop rotation. Plant something that resists onion downy mildew next year so that the fungus has nothing to grow on.

Since this pathogen can survive most winters, it is also important to practice good garden hygiene, collecting and destroying dead onion matter at the end of the season.

Moldy onions are a common problem both before and after harvest. Aspergillus niger is a common onion disease that causes black mold, including moldy spots, streaks, or patches. It's not only worth knowing about if you're growing onions, as the same fungus causes black mold on garlic, too.

Onion Black Mold Info

Onion black mold most commonly occurs post-harvest, affecting bulbs in storage. It can also occur in the field, usually when bulbs are at or near maturity. The fungus enters the onion through wounds, either at the top, on the bulb, or in the roots, or it enters through the drying neck. Symptoms are most commonly seen at the top or neck and may move down. Sometimes black mold destroys the whole bulb.

A. niger is abundant on rotting plant material, and it’s also plentiful in the environment, so you can’t entirely eliminate exposure to this microbe. Therefore, the best methods of onion black mold control involve prevention. Sanitation measures (cleaning up your garden beds) will help prevent black mold problems. Ensure good drainage in the field to prevent development of this disease. Consider rotating onions with other crops that are not in the Alliaceae (onion/garlic) family to prevent a disease problem in the next season.

The other major prevention measures involve careful harvest and storage. Avoid damaging or bruising the onions as you harvest them, because wounds and bruises allow the fungus to enter. Properly cure onions for storage and choose varieties that are known to store well if you plan on storing them for months. Eat any damaged onions immediately, because they won’t store as well.

What to Do with Onions with Black Mold

Mild A. niger infections appear as black spots or streaks around the top of the onion and possibly on the sides – or the whole neck area may be black. In this case, the fungus may have invaded just the dry outer scales (layers) of the onion, producing spores between two scales. If you peel off the dry scales and the outermost fleshy scale, you may find that the inner ones are unaffected.

Onions that are mildly affected are safe to eat, as long as the onion is firm, and the moldy area can be removed. Peel off the affected layers, cut an inch (2.5 cm.) around the black portion, and wash the unaffected portion. However, people with an allergy to Aspergillus shouldn’t eat them.

Severely moldy onions are not safe to eat, especially if they have turned soft. If the onion has softened, other microbes may have taken the opportunity to invade along with the black mold, and these microbes could potentially produce toxins.

Ah, the noble onion. Few of our favorite dishes would be quite as good without it. For the most part, these alliums are easy to grow and have few pests or problems; however, tip blight in onions is a potential threat to yields. What causes onion tip blight? It may be a naturally occurring process in mature plants, but in young plants, this onion disease may indicate a nutritional deficiency or a fungal issue. The problem may also be cultural. Read on to answer the question, "Why are my onions' tips burnt?", and find some preventatives and solutions.

What Causes Onion Tip Blight?

Wind, sun stress, excess soil salts, and other environmental factors can cause onion tip burn. There may also be soil pathogens or even a lack of an important nutrient. Given all the potential causes of browning, dry tip foliage, it can be hard to decide what is affecting the plant.

The first thing to do is decide if the correct cultivation and site conditions are being met. If that is the case, the issue may have to do with a fungus. Vetting the causes of plant problems can be vexing.

In many cases, you just need to look at the soil and your planting procedures. If you're learning how to grow onions, then they need well-draining soil, lots of sun, good spacing, and plenty of nitrogen and phosphorus.

In high heat, full sun locations, it is not uncommon to see tips burn; however, providing shade does little to reduce the incidence of tip burn in onions.

Providing the necessary nitrogen may increase the salt levels in soil, causing brown tips. A soil test is beneficial to see what macro and micronutrients are present in the soil, since too much nitrogen can cause the problem but too little phosphorus can too.

Insects and Onion Tip Burn

Once you are sure your soil and growing conditions are favorable, finding out what causes onion tip blight may be right under your nose. Moisture stress may be encouraging thrips, tiny cigar-shaped larvae, or the adults, slightly larger, winged, and dark-colored. They feed on plant sap from the leaves and their behavior can cause discolored leaf tips. Temperatures higher than 80 degrees Fahrenheit (30 C.) seem to encourage thrip presence.

Leaf miner damage also encourages tip burn in onions. Use organic pesticides, such as neem oil, to combat these tiny pests. Both are more prevalent in early-season crops, crowded stands, and failure to rotate crops.

Fungal Tip Blight on Onions

Tip blight on onions is a named disease that stems from fungi. Fusarium is just one fungus that starts out in the leaf tips, causing them to brown and wilt. Eventually, the disease progresses into the bulb. It is a soil-borne fungus. Botrytis causes foliar damage as well. It produces necrotic lesions that develop into tip burn and blight. Both fungi are present in high humidity and plenty of moisture. Extreme heat seems to minimize the presence but temperatures below 80 degrees Fahrenheit (30 C.) seem to encourage their activity. Sulfur sprays early in the season can help prevent damage from many fungal problems.

Onion botrytis leaf blight, often known as “blast,” is a common fungal disease that afflicts onions grown around the world. This onion disease spreads rapidly, significantly affecting quality and yield when harvest time rolls around. Below, we have provided helpful information on onion botrytis leaf blight prevention and its control.

Symptoms of Botrytis Leaf Blight on Onions

Onions with botrytis leaf blight display whitish lesions on the leaves, usually surrounded by silver or greenish white halos. The centers of the lesions may turn yellow and take on a sunken, water-soaked appearance. Botrytis leaf blight on onions is most common on older leaves.

Causes of Onion Botrytis Leaf Blight

Botrytis leaf blight on onions is most likely to develop as a result of heavy rainfall, extended periods of relatively cool, damp weather, or overwatering. The longer the leaves remain wet, the more severe the outbreak. When foliage remains wet for at least 24 hours, the risk of developing botrytis leaf blight is high. Although it is less likely, the disease can occur when leaves are wet for only seven hours.

Temperature is also a factor. Onions are most susceptible when temperatures are between 59 and 78 degrees F. (15-25 C.). The disease takes longer to develop when temperatures are cooler or warmer.

Leaf Blight Control of Onions

Unfortunately, no onions currently on the market are resistant to botrytis leaf blight. However, there are steps you can take to prevent or slow the disease from spreading. Plant onions in well-drained soil. Soggy soil promotes fungal disease and rot.

If possible, avoid overhead irrigation and water at the base of the plant. Water early in the day so the foliage has time to dry before temperatures drop in evening, especially if you use a sprinkler. Limit irrigation late in the season when onion tops are drying. Don’t fertilize late in the season either.

Fungicides may slow the spread of onion botrytis leaf blight if applied at the first sign of disease, or when weather conditions indicate the disease is imminent. Repeat every seven to ten days.

Keep weeds under control, especially wild onions and other alliums. Rake the area and destroy plant debris after harvest.

Practice crop rotation of at least three years, with no onions, garlic, or other allium planted in that soil during the “off” years.

Have you ever seen purple blotches on your onions? This is actually a disease called ‘purple blotch.’ What is onion purple blotch? Is it a disease, pest infestation, or an environmental cause? The following article discusses purple blotch on onions, including what causes it and how to manage it.

What is Onion Purple Blotch?

Purple blotch in onion is caused by the fungus Alternaria porri. A fairly common disease of onions, it first manifests as small, water-soaked lesions that rapidly develop white centers. As the lesions progress, they turn from brown to purple with a halo of yellow. Often the lesions merge and girdle the leaf, resulting in tip dieback. Less commonly, the bulb becomes infected through the neck or from wounds.

Fungal growth of spores of A. porri is fostered by temperatures of 43 to 93 degrees F. (6-34 C.) with the most optimal temperature of 77 degrees F. (25 C.). Cycles of high and low relative humidity encourage spore growth, which can form after 15 hours of relative humidity greater than or equal to 90%. These spores are then spread by wind, rain, and/or irrigation.

Both young and mature leaves affected by thrip feeding are more susceptible to purple blotch in onions. Onions with purple blotch present symptoms one to four days after infection. Onions infected with purple blotch become defoliated prematurely which compromises bulb quality, and lead to storage rot caused by secondary bacterial pathogens.

Managing Purple Blotch in Onion

When growing onions, use pathogen-free seeds/sets where possible. Ensure that plants are properly spaced and keep the area around the onions weed-free to increase circulation, which will allow the plants to dry from dew or irrigation more rapidly.

Avoid fertilizing with food that is high in nitrogen.

Control onion thrips, whose feeding makes the plants more susceptible to infection.

Purple blotch can overwinter as mycelium (fungal threads) in onion debris, so it is important to remove any debris prior to planting in successive years. Also, remove any volunteer onions which may be infected. Rotate your onion crops for at least three years.

Harvest onions when conditions are dry to avoid neck injury, which may act as a vector for infection. Let the onions cure before removing the leaves. Store the onions at 34 to 38 degrees F. (1-3 C.) with a humidity of 65 to 70% in a well-aerated, cool, dry area.

If need be, apply a fungicide according to the manufacturer’s instructions. Your local extension office may be of assistance steering you to the correct fungicide for use controlling purple blotch in onion crops.

Help, my onions have streaked leaves! If you have done everything by the onion “book” and still you have onion leaf variegation, what could be the issue – a common onion disease, a pest of some sort, or a disorder of onions? Read on to get the answer to “why are my onions variegated?”

About Onion Leaf Variegation

As with most any other crop, when growing onions, they may be susceptible to certain pests and disease as well as disorders. Most of the diseases are fungal or bacterial in nature, while disorders may be the result of weather, soil conditions, nutrient imbalances, or other environmental concerns. In the case of onions with streaked or variegated leaves, the cause is most likely a disorder called chimera in onions. What causes chimera onions and are onions with streaked leaves still edible?

Chimera in Onions

If you are looking at leaves of varying shades of green to yellow to white in color that are either linear or mosaic, the most likely culprit is a genetic abnormality called chimera. This genetic abnormality is considered a disorder, although it is not affected by environmental conditions.

The yellow to white coloring is a deficiency in chlorophyll and can result in stunted or even abnormal plant growth if severe. A rather rare occurrence, chimera onions are still edible, although the genetic abnormality may alter their taste somewhat. To avoid chimera in onions, plant seed that is certified to be free of genetic abnormalities.

Wethersfield red onions (Allium cepa) are among the best-known of America's heirloom onions, with a rich history inextricably tied to the nation's earliest years. Read on to learn more about Wethersfield onions.

Wethersfield Heirloom Onions

Wethersfield red onion plants were grown and developed in Wethersfield, Connecticut, a village located in the rich Connecticut River Valley, near Hartford and not too far from New Haven. Many fine agricultural crops were cultivated in the area, but the red onions definitely put the town on the map. Unsurprisingly, the town was once known as 'Oniontown."

Yankee Magazine notes that the attractive braided skeins could be seen hanging from nearly every doorway and rafter. Even today, the town celebrates its rich agricultural heritage with parades and festivals honoring the heirloom onions. With their plump, somewhat flat shape and reddish-purple skin, Wethersfield onions are lovely to look at.

Residents of Wethersfield were understandably proud of the rolling onion fields and savory aroma. According to the New England Historical Society, residents were also proud of the hard-working Wethersfield red onion maidens - young girls who planted and harvested the onions every year. The girls were also said to be the best cooks around- probably because they spiced up most dishes with the pungent red onions.

The New England Historical Society also notes that at one time millions of Wethersfield onions were exported to the South and West Indies. However, exports, along with the shipbuilding trade, declined substantially by the 1830s. During the Civil War era, Wethersfield red onions were afflicted by a blight known as pink root. As a result, many onion growers were forced to diversity their crops, often switching to products that didn't require long-distance shipping, such as corn, potatoes, milk, cream, eggs and butter.

Tobacco also became an important commodity, and many farmers supplemented their income with fishing. However, if you're interested in growing Wethersfield red onions, Wethersfield is still home to two seed companies that have been in business since the nineteenth century. The plants are vigorous and easy to grow.

You may think an onion is an onion is an onion – all good on a burger or diced into chili. Actually, there are many varieties of onion. To make it easier, onions have been categorized into three basic types of onions. Each kind of onion has attributes that make it the best type of onion for different regions or conditions. If I’m confusing you, read on for clarification of the kinds of onion plant varieties and the perfect onion for different climates.

About Onions for Different Climates

If you're learning how to grow onions, then you need to know there are three basic types: short-day, long-day, and day-neutral. Each of these onion plant varieties is more suited to a particular region than another. For instance, in the north, from San Francisco to Washington, D.C. (zone 6 or colder), summer days are long, so you would grow long-day onions. In the south (zone 7 and warmer), summer days don’t swing much in length in comparison to winter days, so grow short-day onions. Day-neutral onions, sometimes referred to as intermediate, form bulbs in any USDA zone. That said, they are perfectly suited for zones 5 and 6.

Growing the Three Kinds of Onions

Short-day onions form bulbs when given 10 to 12 hours of daylight, perfect for southern regions. They require a mild winter climate in zone 7 or warmer. While they can be planted in northern locations, the bulbs tend to be smaller. Grown in warm climates, they mature within 110 days when planted in the fall. Cooler areas can expect maturity in about 75 days when planted in the spring. Short-day varieties of onion include:

• Georgia Sweet
• Sweet Red
• Texas Super Sweet
• Texas Sweet White
• Yellow Granex (Vidalia)
• White Granex
• White Bermuda

Long-day onions are planted in winter or early spring and mature in 90 to 110 days. They require 14 to 16 hours of daylight and are usually grown in the northern regions with a USDA of zone 6 or colder. This type of onion makes a great storage onion. Varieties of this type of onion include:

• Walla Walla Sweet
• White Sweet Spanish
• Yellow Sweet Spanish

Day-neutral onions form bulbs when exposed to 12 to 14 hours of daylight and are planted in the fall in mild winter climates and in early spring in northern climates. These super sweet onions mature in 110 days and are most ideal for USDA zones 5 or 6. A popular variety of day-neutral onion is the appropriately named Candy Onion but there’s also Sweet Red and Cimarron.

Sweet onions are starting to become wildly popular. What are sweet onions? They get their name not from their high sugar, but their low sulfur content. A lack of sulfur means that the onion bulbs have a milder, smoother taste than other types of onions. In fact, the best commercially grown sweet onions come from parts of the world that have naturally low levels of sulfur in the soil, like Vidalia, Georgia.

Sweet onion growing can be a little tricky, but if you're experienced in growing onions, then it's worth giving it a try.

How to Grow Sweet Onions

The key to successful sweet onion growth is giving the plants enough time to form really large bulbs. The best way to do this is to plant them in late summer or early autumn and let them grow through the winter. This means sweet onion plants grow best in climates that have mild winters.

The most popular sweet onion plants for winter growing are called short-day onions, a variety that still grows well during the short days of winter. These onions tend to be hardy down to 20 degrees F. (-7 C.). Other varieties, called intermediate day, are hardy down to 0 degrees F. (-18 C.) and can survive in colder climates. If your winters are very cold, it’s also possible to start sweet onions indoors and transplant them out in the spring, though the bulbs will never get as big.

Sweet onions like well-drained, fertile soil. They are heavy feeders and drinkers, so caring for sweet onions involves watering them frequently and applying regular fertilizer in the spring when the bulbs are forming. Avoid fertilizers with sulfur, as this will make the onions taste less sweet.

Short day sweet onions should be ready to harvest in early to midspring, while intermediate day varieties should be ready in early to midsummer.

In some parts of the U.S., onion maggots are without a doubt the most serious pest of plants in the onion family. They are a problem for those growing onions, leeks, shallots, garlic, and chives. Find out about the identification and control of onion maggots in this article.

What are Onion Maggots?

Onion maggots are the larval form of a little gray fly that looks a lot like a common housefly except that it is only one-fourth inch (6 mm.) long. The small, cream-colored maggots infest the bulbs, riddling them with tunnels. The damage leaves the bulbs susceptible to invasion by bacteria.

The maggots have about three generations each year. The first generation is the largest and causes the most damage. The last generation attacks just before harvest. This generation leaves the bulbs susceptible to rot during storage.

The parents of onion maggots, which are small, gray flies, are hard to distinguish from any other fly. The females lay their eggs in the soil where onions grow in order to get their offspring off to a good start in life. When they hatch, the maggots feed on the underground onion bulbs for about three weeks before they leave the bulb and move out to the soil where they pupate. They later emerge as adults that begin the process all over again.

How to Get Rid of Onion Maggots

Onion maggot damage includes a poor rate of germination and survival in young plants. Older plants may have limp, yellow leaves. The bulbs may show signs of soft rot while they are still in the ground, but they sometimes don't begin to rot until after harvest.

Crop rotation is one of the most important aspects of onion maggot control. The maggots feed only on members of the onion family. If newly hatched maggots don't find a food source, they won't survive.

When you thin your plants, remove and destroy the culls, which also serve as a food source. You should also completely remove any crop debris remaining at the end of the year. The insects like to pupate and overwinter in areas with large pieces of organic matter.

To avoid providing them with a comfortable hiding place, make sure all compost is completely decomposed before adding it to areas where you are growing onions.

For the most part, insecticides available to home gardeners are ineffective. Contact insecticides never reach the maggots, which are hidden away inside the bulbs. The insects have developed resistance to systemic insecticides.

Companion planting onions is one of the easiest organic ways to encourage healthier growth in your garden. If you’re already familiar with how to grow onions, pairing them with the right neighboring plants can help naturally repel pests and support stronger growth. Onions are especially good companions thanks to their strong scent, which deters many common bugs, and understanding the wider principles of companion planting vegetables makes it easier to plan a productive, balanced garden.

What Can I Plant with Onions?

Far and away the best onion plant companions are members of the cabbage family, such as:

• Broccoli
• Kale
• Brussels sprouts
• Cabbage

This is because onions naturally repel pests that love cabbage family plants, like cabbage loopers, cabbage worms, and cabbage maggots. Onions also naturally deter aphids, Japanese beetles, and rabbits, meaning that good companion plants for onions are any plants that often fall victim to them. Some other particularly good onion plant companions are:

• Tomatoes
• Lettuce
• Strawberries
• Peppers

Bad Companion Plants for Onions

While onions are mostly good neighbors across the board, there are a couple of plants that should be kept away from them because of chemical incompatibility and possible flavor contamination. All varieties of peas and beans can be detrimental to onions. The same goes for sage and asparagus. Another bad onion neighbor is actually other onion plants. Onions frequently suffer from onion maggots, which can travel easily from plant to plant when they’re spaced close together. Other onion-like plants, such as garlic, leeks, and shallots, are common targets of onion maggots as well. Avoid planting them near onions so the onion maggots can’t travel easily. Scatter your onions throughout the garden to prevent the spread of onion maggots and to benefit as many other plants as possible with the onions’ presence.

It’s one of the best kept secrets that there are some vegetables you need only buy once. Cook with them, place their stumps in a cup of water, and they’ll regrow in no time at all. Green onions are one such vegetable, and they work especially well because they’re usually sold with their roots still attached. Keep reading to learn more about how to grow green onions in water.

Can You Regrow Green Onions in Water?

We are often asked, “Can you grow green onions in water?” Yes, and better than most vegetables. Growing green onions in water is very easy. Usually, when you buy green onions, they still have stubby roots attached to their bulbs. This makes regrowing these useful crops an easy endeavor.

How to Grow Green Onions in Water

Cut the onions a couple inches (5 cm.) above the roots and use the top green part to cook whatever you like. Place the saved bulbs, roots down, in a glass or jar with just enough water to cover the roots. Place the jar on a sunny windowsill and leave it alone apart from changing the water every few days. Green onion plants in water grow very quickly. After just a few days, you should see the roots growing longer and the tops beginning to sprout new leaves. If you give them time, your green onion plants in water should grow right back to the size they were when you bought them. At this point you, can cut the tops off to cook and start the process right over again. You can keep them in the glass or you can transplant them into a pot. Either way, you’ll have a virtually inexhaustible supply of green onions for the cost of a single trip to the produce section of your grocery store.

To new gardeners, rolling down onion tops may seem like a questionable thing to do, but many gardeners think folding onion tops before harvesting onions is a useful practice. Read on to learn all about it.

Why Do You Fold the Tops of Onions?

If you plan to use them right away, folding onion tops isn’t really necessary. However, if your goal is to store onions for the winter, rolling down onion tops encourages the onion to turn brown and stop taking up water, thus boosting the final process of ripening. When sap no longer flows through the onion plant, growth stops and the onion will soon be ready to harvest and cure for storage.

When to Fold Onion Tops

This is the easiest part of growing onions. Fold or bend onion tops when they begin to turn yellow and fall over on their own. This occurs when the onions are large and the tops are heavy. Once you’ve folded the tops of the onions, leave them in the ground for several days. Withhold water during this final ripening period.

How to Roll Down Onion Tops

The technique for folding tops is totally up to you. If you’re an orderly gardener and messiness drives you crazy, you can fold the tops over carefully, creating rows that keep your onion bed tidy. On the other hand, if you tend to be casual about the appearance of your garden, simply walk through the onion patch and step on the tops. Don’t, however, step directly on the onion bulbs.

Harvesting After Folding Onion Tops

When the onion tops turn brown and the onions are easy to pull from the soil, it’s time to harvest the onions. Onion harvest is best performed on a dry, sunny day.

A wet growing season is bad news for anyone trying to grow onions. Many diseases, most of them fungal, invade the garden and ruin onions in times of warm, moist weather. Read on to find out about onion diseases and their control.

Onion Diseases and Their Control

It's difficult to tell the difference between the many diseases affecting onion plants. Even the experts often have to rely on laboratory tests for a definitive diagnosis. Fortunately, you don't have to know exactly which disease has infected your plants to take action.

Onion plant diseases arise during warm, moist weather and most have similar symptoms, which include spots and lesions on leaves and bulbs, areas that look as though they are water-soaked, browning foliage, and toppling.

There is no method of treating diseases of onion, and you can't reverse the damage. The best course of action is to focus on next year's crop so that it doesn't happen again. Here are some growing tips to help prevent the introduction of diseases into your onion crop:

• Place your onion patch on a three or four year rotation. You can grow other crops in the area in the intervening years, but avoid members of the onion family, such as garlic and scallions, as well as ornamental alliums.
• Avoid fertilizing with nitrogen after midseason. Nitrogen fertilizer delays the development of bulbs and gives diseases more time to infest your crop.
• Discard culls and other organic debris promptly. Fungi overwinter in debris left in the garden, and this includes onion plant matter that you till into the soil. Good sanitation helps keep disease pathogens out of the garden.
• Take care when using a cultivation tool around onions. Cuts in the bulbs and foliage create an entry point for disease spores.
• Buy seeds, plants, and sets from a reputable garden center. Buy material that is certified disease-free whenever possible.
• Disease spores can also invade onions after harvest. Spread onions on a table or screen to dry after harvest. Make sure air circulates freely around them.
• Pull and discard diseased bulbs. Disease spores can spread by wind and by water splashing soil onto the plant. The spores also travel from plant to plant on your hands, clothing, and tools.

It’s spring and the garden or farmer’s market, as the case may be, is brimming with fresh, tender, delectable veggies. One of the most versatile is the spring onion. This beauty will bring tears to your eyes (get it?). So what is a spring onion? Keep reading to learn about spring onion cultivation and some uses of these popular types of onion.

What is a Spring Onion?

There seems to be some confusion surrounding exactly what a spring onion refers to. This could be that it is referred to as a green onion in Canada and the United Kingdom. Then the green onion is often called a scallion, so that identification becomes somewhat perplexing. Simply put, a green onion in the United States is also a scallion. Same animal…ahem, allium.

What is the difference between a green onion (scallion) and a spring onion then? A green onion has slender, green fronds growing above ground with a small white, underground white stem. Green onions never grow a bulb but stay forever with a slight white stem end.

Spring onions (Allium fistlosum) look much akin to scallions, but they have a small onion bulb at the base. They are a product of many different onion varietals and can be red or white. The bulb size varies depending upon when it is picked and what type of onion it is but can be as small as a scallion or as wide across as a softball. It tastes like a muted version of the mature onion varietals, only with a much mellower, sweeter flavor.

Uses for Spring Onions

Spring onions can be used much like mature onions or scallions. They will have a bolder flavor than scallions, however, so if you don’t want such an “oniony” burst, use the scallion. Spring onions are ideal on the grill, brushed lightly with olive oil (including the greens!), and grilled to a charred exterior and a sweet, succulent inside. They also make a terrific, sweet onion pickle “relish” that is sublime over hot dogs and brats. They are delicious when sliced thin and sautéed or tossed into the wok.

Care of Spring Onions

Spring onion cultivation should be done in the, you guessed it, spring, from March to July. Harvest will be from March to May. Growing spring onions is easy and because they take up so little space and have a shallow root system, the plants can be tucked in here and there in the garden or into containers.

You can buy seeds for sowing or if you had a previous crop (or a friend did), allow the seed heads to mature, and then lop them off. Put the seed head in a paper bag and allow it to dry for two weeks. Voila, you now have seeds. Store them in a cool, dry area.

Sow the seeds indoors or out in a prepared bed. Rake the bed clear of debris and stones and amend the soil with some organic soil conditioner. Spring onions like a soil pH of 6.0 to 7.0 in well-draining, humus-rich soil and full sun exposure. Sow seed ¼ inch (6 mm.) deep in rows 6 inches (15 cm.) apart. Don’t worry too much about how close together the seeds are otherwise. You can always thin them and then don’t throw the thinnings away! Toss them into a salad or into a stir fry at the last moment of cooking.

Care of spring onions thereafter is minimal. Be sure to provide them with one inch (2.5 cm.) of water per week, depending upon rainfall. Feed them with a liquid fertilizer two to three times during the growing season. Keep the area around the onions weed-free.

You can keep growing spring onions year-round either outside or in a greenhouse through succession planting every three to four weeks for a steady supply of this luscious allium. Your spring onions will be mature and ready to eat in between 8 to 12 weeks.

Winter onions are a form of multiplying onion grown for their flavorful green tops and small bulbs, which are typically harvested at around 3 inches (7.5 cm) in diameter or less. They make up several onion varieties grown by home gardeners and differ from single-bulb onions by forming clusters and offering a slightly milder flavor. While especially well suited to fall planting and overwintering, winter onions can also be grown using many of the same techniques as planting onions at other times of year. They are also commonly known as potato onions or ground onions.

How to Grow Winter Onions

Winter onions can actually be planted in spring or fall. However, onions planted in fall generally produce larger yields. Many gardeners like to plant onions in fall, then save a few small onions in a dry location for planting in spring. Winter onions can be planted any time the ground can be worked – usually between October and December in most climates – or two to three weeks before the first hard freeze. Growing winter onions require full sun, as the onions won’t grow in shade. Plant the onions 2 to 4 inches (5 to 10 cm.) deep, allowing 4 to 6 inches (10 to 15 cm.) between each bulb. Water well. The onions are underground and tolerate cold weather. However, a layer of mulch is helpful for overwintering onions in cold, northern climates. You can also plant winter onions in a container. Keep the container near the kitchen door and harvest onions for use throughout the winter. A container with a width of at least 18 inches (45 cm.) is best.

Harvesting Winter Onions

Harvest the first winter onions two to three months after planting. Although you can harvest earlier, the onions will be very small and they won’t have time to multiply. (When allowed to mature, each bulb usually produces seven or eight bulbs.) Continue to pull or dig onions until spring. To save a few for fall planting, allow the tops to dry before pulling, then lay the onions in the sun for a few days so the outer covering dries. Store the onions in a cool, dry location until fall planting time.

Best Winter Onions

Many types are available and the best way to determine the best winter onions for your area is to experiment with different varieties. Example of popular winter onions include:

• White multiplier onions, which develop thumb-size bulbs
• Yellow potato onions, heirloom onions that have been around for well over 200 years.

Others include:

• Kentucky Hill
• Red
• Yellow
• Greeley’s

Also known as spring onion, Welsh bunching onion, Japanese leek or stone leek, Welsh onion (Allium fistulosum) is a compact, clumping type of onion cultivated for its ornamental value and mild, chive-like flavor. Welsh onion plants are perennial in USDA plant hardiness zones 6 through 9.

Growing Welsh onions is much easier than growing onions of the regular variety, so don’t hesitate to plant these tasty, attractive plants where you can enjoy the hollow, grassy leaves and chive-like blooms.

Planting Bunching Onions

Plant Welsh onion seeds indoors in March, using a regular commercial potting soil. Keep the soil lightly moist until the seeds germinate, which generally takes seven to 10 days.

Plant the seedlings in your garden after about a month, when all danger of frost has passed. Full sun is best, but Welsh onion plants tolerate a bit of light shade. Allow about 8 inches between each seedling.

If you have access to established plants, you can easily propagate new plants by division. Simply dig up clumps and pull them into individual bulbs, then replant the bulbs in soil that has been cultivated ahead of time.

Dig an inch or two of compost into the soil to get the plants off to a good start.

Caring for Your Growing Welsh Onions

Welsh onion plants are remarkably trouble free. The plants benefit from regular irrigation, especially during hot, dry weather, but they are relatively drought tolerant. No fertilizer is required, especially if you add compost to the soil at planting time. However, if your soil is poor or growth appears stunted, provide a light application of 5-10-5 fertilizer once a year, in early spring.

Harvesting Bunching Onions

Pull an entire plant as needed when Welsh onions are 3 to 4 inches tall, or snip off pieces of leaves for seasoning soups or salads. As you can see, there's little effort involved when growing or caring for Welsh onion plants in the garden.

Eighty-seven percent of the onion varieties used in cooking are culled from the common yellow onion. While there are many varieties of yellow onion, its less-utilized cousin, the red onion, has its place in the kitchen for its mild, sweet flavor and brilliant color. So, are red onions easy to grow? When is planting and harvesting time for red onions? Read on to learn more about these hugely versatile types of onions.

Are Red Onions Easy to Grow?

Growing red onions is as easy as any other type of onion. All onions are biennials, meaning they take two years to complete their life cycle. In the first year the seed grows, forming modified leaves and tiny underground bulbs. In the succeeding year, red onion bulbs mature until they're ready to harvest. Most gardeners plant onion sets the second year that small red onion bulbs to hasten the maturation and harvest of the onions.

Planting and Harvesting Red Onions

With regards to white vs. red onions, there's no difference when growing red onions as opposed to growing onions in general. There is a difference in flavor with white onions milder than red and having a shorter storage life than red onions. Both types of onion come in a multitude of varieties with varying planting times, thus different harvesting times.

How to Grow Red Onions

To get onions off to a good start, mix an organic or time-release fertilizer into the soil prior to planting. Make sure the fertilizer is beneath the planting furrow. This is called “banding” and makes sure the nutrients are exactly where the young onion roots can find them. Mix a 2 inch (5 cm.) layer of compost into the soil before adding the fertilizer.

All onions need plenty of sun and well-draining soil with a pH between 6.0 and 6.8. Set the onion bulbs 1 to 2 inches (2.5-5 cm.) deep so the roots are well covered but the neck isn't set too deeply. Space the plants 6 inches (15 cm.) apart in furrows 12 inches (31 cm.) apart.

Water the onions until they are wet, but not drenched. Onion roots are shallow, so they need a consistent supply of water, which will also garner sweeter onions. You can lay a light layer of grass clippings or other fine mulch around the onions, but be sure to keep it away from the onion tops which need full access to the sun.

When to Harvest Red Onions

Okay, so you have patiently waited throughout the summer and are itching to dig up the red onions and try them. The question is, when is the right time to harvest red onions?

You can pull onions after a few weeks if you just want to use them as scallions, but for full-sized onions, you must be patient and let them mature. Onions are ready to harvest when the bulbs are large and the green tops begin to yellow and fall over.

Stop watering the onion when around ten percent of the tops begin to fall over. You can now harvest the onions or leave them in the ground to be stored and used as needed.

To harvest the onions, dig them up and shake off the loose soil. Lay them out to cure with the tops still attached, in a warm, airy place. Keep the onions dry with good air circulation so they don’t rot.

As the onions cure, the roots shrivel and the necks dry out. Allow the onions to cure for seven to ten days and then either braid the tops for storage or remove the tops and roots with pruning shears.

Store the cured onions in a cool, dry place between 35 and 50 degrees F. (1-10 C.).

Ahh, the zippy taste of onions - they're found in nearly every recipe and great additions to salads and sandwiches. There are also soooo many to choose from, including heirloom varieties rich with history. One such plant is the Long Red Florence onion.

Red of Florence Onion Plant History

Onions are among some of the oldest cultivated plants in history. Ancient Egyptians ate them commonly, even supplying hungry builders of the Great Pyramids with the scrumptious, albeit pungent, treats. The origin of the onion (Allium cepa) is not known with certainty but may perhaps be Central or Western Asia. Its use and popularity eventually spread throughout Europe and finally the U.S. with the settling of the New World. Long Red Florence is an Italian heirloom originating from Tuscan, Italy sometime in the 1800s.

This heirloom is also known by a number of other names: Rouge de Florence, Rossa di Firenze, Rossa Lunga Di Firenze, Rossa di Toscana, Florence Simiane, Italian Torpedo or Italian Red Torpedo and Long de Florence Simane. Not that other onion varieties aren't appealing or anything, but these are exceptionally so to me - likely because I have a thing for stuff outside the norm.

These onions are elongated in shape (resembling a torpedo) and red in color. Their mildly sweet flavor and tenderness, along with ease of growth, make the onions yet another winner in the garden.

Growing Long Red Florence Onions

The onion is a cool-season vegetable that can be successfully grown just about anywhere. This particular variety is a long-day type. It can be sown in spring and fall in milder climates. Start onion seeds 4-6 weeks before the last frost, about ¼ inch deep, in soilless mix.

Once seedlings are large enough and the temps have warmed sufficiently, you can transplant them out, spacing about 8-12 inches. And like most onions, they make great companions to other veggies in the garden (with exception to beans or peas anyway). Depending on the size you want them, your onions will be ready for harvesting anytime between 100-120 days from transplant, sometimes as early as 60 days. Successive plantings every 2 to 4 weeks will ensure a continuous supply throughout the season too. Eat them in salads or cook like traditional onions.

Bulb vegetables are some of the easier plants to grow in the garden, provided you can keep the pests and diseases at bay. Good onion care requires lots of patience and a watchful eye. After all, if you can catch problems like pink root rot in onions early, you may be able to save at least part of your harvest. While pink root sounds like something you'd get from a high-end salon, it's actually a problematic disease in onions. Do you know how to tell if your onions are afflicted? If not, this article will help.

What is Pink Root?

Pink root is a disease that primarily attacks onions, though many other plants, including cereal grains, can be carriers. The fungal pathogen, Phoma terrestris, is able to survive many years in the soil without a host crop but reactivates and moves swiftly into weakened or stressed onions when it detects them. The plant then becomes unthrifty and will grow much more slowly than other non-diseased plants nearby.

Pink root onions are named for the distinctive pink roots that appear on an infected, but still growing, onion. As the fungus feeds on the onion roots, they first turn a light pink color, then dark purple.

Advanced disease is generally found toward the end of the growing season; affected onions present with black, dry, or brittle roots and small or nonexistent bulbs.

Onion Pink Root Treatment

The only way to confirm pink root onion disease is to uproot suspicious onions and check their roots for the distinctive discoloration. Once you're positive your plants are infected, you can attempt to limp them along by making growing conditions unfavorable to the pink onion fungus.

Wait to water until your onions are dry around the bulb's base and increase your fertilization efforts to keep your plants as healthy as possible. Unfortunately, even with great care, you're likely to be disappointed in your harvest. Prevention is, sadly, much easier than curing a sick stand of onions.

A six-year crop rotation can be employed in the future to minimize the impact of pink root on your onions, but don't plant cereal crops where you plan to plant onions, or you'll be no better off. Also, be sure to amend your garden soil with lots of organic material to promote better drainage and discourage fungal growth.

Many of us grow fresh herbs on the kitchen windowsill or another sunny nook. It's so convenient to snip a sprig of thyme or another herb to freshly flavor our home-cooked meals and give them some pizzazz. Along with herbs, garlic and onions are a staple of my menus; so what about growing onions vertically indoors?

How to Grow a Vertical Onion Garden

Vertical gardening with onions is a great way to garden for those with limited space. It's also a great wintertime project when you're yearning to see something green growing amidst the freezing temps and snowstorms. This project is fun to do with the kids, although the first part should be done by an adult. It is also an awesome way to recycle and repurpose something we have far too much of on this planet – plastic bottles.

Learning how to grow a vertical onion garden is a very simple process. This “do it yourself” project of growing onions vertically in a bottle is so easy, in fact, that you very likely have the necessary items to accomplish it just lying around the house.

The first thing that you need for growing onions vertically in a bottle is – you guessed it, a bottle. A run-of-the-mill 5-liter plastic bottle, to be exact. You may have one waiting to be recycled, leftover from the kids' juice or your post-workout water.

The next step is the most difficult part of this project, and that isn't saying much. You'll need to cut holes in the plastic bottle; this is where the adult should do the work if done with children:

1. Clean the bottle thoroughly, and for aesthetic purposes, remove the label.
2. Cut the neck from the bottle so you have room to place the onion bulbs.
3. Cut alternating holes around the bottle large enough to accommodate the bulb size. You can use scissors, a box cutter or utility knife, or a heated metal tool to melt holes into the plastic.
4. Now begin layering onion bulbs and soil in a circular pattern, alternating between the two.
5. Water the bulbs and replace the top of the bottle to help keep the soil and moisture in.
6. Place the onion in a bottle on a sunny windowsill that gets plenty of sun during the day.

Indoor Onion Care

Indoor onion care only requires some consistent moisture and plenty of sun. Within days, your onions should sprout, and green leaves will start to poke out of the holes. Soon you'll be ready to snip fresh onion greens or pluck the entire onion to embellish your soups, salads, and more.

Can onions tolerate cold temps? That depends on how cold and at what age the onions are. If you're just learning how to grow onions, then it might surprise you to know they are quite hardy and can withstand light freezes and snow. Young starts can be susceptible to heavy freezes and require protection. Onion cold and frost protection are simple, but you need to apply the steps before a hard freeze threatens new sprouts.

Can Onions Tolerate Cold Temps?

Protecting onion plants from cold isn't necessary for some parts of the country, but in the north and even temperate west, severe weather is still possible. New onions and frost can cause damage to the tender young stalks and fragile bulbs. The worst thing that usually happens is the bulb freezes and then rots after it thaws. There are ways, however, to give onion cold and frost protection that are quick and easy.

Onions thrive in a variety of temperature ranges, but they produce the best at 55 to 75 degrees F. (12-23 C.) and most varieties are hardy to 20 degrees F. (-6 C.). They produce bigger bulbs when these temperatures are achieved for the longest time because that allows foliage to form, which will help fuel bulb production. They need a high temperature and low humidity after the bulb forms and curing begins.

Onions also need a long photoperiod to produce large bulbs. Most need between 12 and 15 hours of light, which makes some varieties unsuitable for northern climes. Cold temperatures will slow down bulb production, as do the lower light hours in many northern zones.

How to Protect Onions in Frost

The best way to keep onions and frost apart is with simple mulch. Use an organic mulch that is at least 2 inches (5 cm.) deep when cold and freezing temperatures are expected. Simple bark, straw, pine needles, grass clippings, or other natural mulches are very effective in protecting onion plants from cold. Pull the mulch away from the plants in spring as the ground warms.

If you have enough notice, it is a good idea to water the plants in the morning. Moist soil stays warmer than dry. To prevent any issues in a colder climate, it's best to plant your onions in a raised bed. The deep, fluffy soil will stay warmer and protect the bulbs.

Harvesting and Keeping Onions

Onion bulbs can be harvested when the tops fall over and begin to die back. The bulbs need to be cured for storage. Let them dry in a warm dry area for two weeks or more. It's best to provide good air circulation with a fan. Store onions in a cool, dry location in a ventilated container, like a mesh bag or even a stocking. They can be individually wrapped in foil and stored in the refrigerator for up to a year. Sweet onions have a higher moisture content and, therefore, a shorter shelf life. The really pungent ones are the ones that you can store for longer due to a lower moisture count.

Many onion varieties are available to the home gardener, and most are relatively easy to grow. That said, those learning how to grow onions do have their fair share of issues with onion bulb formation; either the onions don't form bulbs, or they may be small and/or misshapen.

Reasons for No Onion Bulbs

One possible reason for a lack of onion bulb formation is the selection of the wrong type of onion for your area. In their natural environment, onions are biennials that have a two-year life cycle. The first year, the plant bulbs and the second year it flowers. Cultivators of onions grow them as an annual and harvest at the end of the first growing season. Onions are categorized as “long day” or “short day” varieties, with some intermediate varieties available as well. The terms are in reference to the length of daylight during the growing season in a particular area.

• A “long day” onion variety quits forming leaves and begins to bulb when the length of daylight is 14-16 hours.
• “Short day” cultivars make bulbs much earlier in the season when daylight is only 10-12 hours long.

“Long day” onions should be planted north of the 40th parallel (San Francisco on the west coast and Washington D.C. on the east) while “short day” onions do best south of the 28th parallel (New Orleans, Miami). The newest kids on the block are the day neutral varieties of onion which can be planted without regard to latitude -- a big boon to gardeners between the 28th and 40th parallel. Bulb size is in direct correlation to the number and size of leaves (tops) of the onion at the time of bulb maturity. Each leaf corresponds to a ring of the onion and the larger the leaf, the larger the ring.

How to Get Onions to Form a Bulb

Choosing an appropriate onion variety for your region and following the correct planting time is an important factor in getting healthy onion bulbs to form. “Long day” varieties are planted in the early spring. Either start seeds indoors and transplant or plant onion sets directly outdoors.

Note: When starting seeds indoors under a grow light, do so early, even 3-4 months, and start them in cells for stronger root development. Then transplant into the garden at the same depth as the plug so the bulbs form naturally at the correct height.

“Short day” cultivars should be planted mid fall, either directly sown or with onion sets. Grow onions in raised beds about 4 inches (10 cm.) high and 20 inches (50 cm.) across. Dig a 4-inch (10 cm.) trench in the bed and distribute a phosphorus rich fertilizer (10-20-10) 2 or 3 inches (5 to 7.5 cm.) below the transplants, cover with a couple of inches (5 cm.) of soil and plant the onion sets.

Maintain some space between the plants, 1 inch (2.5 cm.) deep and 4 inches (10 cm.) apart. For direct sown onion, thinning is the key to bulb size. Obviously, if there isn't room to grow, you'll get onions that don't form adequate bulbs.

Lastly, while this may not be directly related to a lack of bulbing, temperature will most certainly affect the size and quality of the onion. Cooler temps below 70 F. (21 C.) may retard bulbing in some varieties. In late spring, fluctuation between warm days alternating with cool days may cause the plant to bolt, or flower. Flowering in onions results in a lighter weight bulb with an increased risk of decay and a lower storage life.

Humans have been growing onions for over 4,000 years and yet every year gardeners wonder about how and when to harvest onions for the best flavor. Thankfully, after several millennia of cultivation, we have the answer!

Onions are a popular cool season vegetable you can grow from either seeds, sets, or transplants. Learning how to harvest vegetables is important for every plant in your garden, but especially so for onions. These easy-care cool season veggies can provide a kitchen staple through the fall and winter.

Here's everything you need to know about how and when to harvest onions for delicious flavor all season long.

Readying Onions for Harvest

Your success in harvesting onions will depend on proper planting and care throughout the growing season. Growing onions from seed is a bit more difficult and will take longer before bulbs are ready to harvest. That's why many gardeners choose to grow onions from sets or transplants.

Plant onions sets as soon as the garden can be worked. Rich soil, consistent moisture and cool temperatures help bulb development. It's best to create hills for onions that are to be used for green onions but do not hill those to be used for bulbs.

When to Harvest Onions

In addition to good planting, you need to know when to harvest onions for the best flavor. Harvest tops for green onions as soon as they reach 6 inches (15 cm.) in height. The longer you wait to harvest the green tops, the stronger they become. Any bulbs that have bolted, or formed flower stalks, should be pulled and used right away; they are not good for storage.

It's time to start harvesting onions when their tops naturally fall over and brown. This is usually 100 to 120 days after planting, depending on the cultivar. The ideal onion harvest time is early in the morning when temperatures are not too hot.

How to Harvest Onions

Knowing how to harvest onions is important, as you don't want to damage the plants or onion bulbs. Carefully pull or dig onions up from the ground with the tops intact. You can do this by hand, with a trowel, or with a pitchfork. Be careful not to bruise your onions, as this can make them more susceptible to rot.

Gently shake the soil from the bulbs. You can use a soft brush or a gloved hand to remove excess dirt, but don't wash your onions yet. They still need to cure before you can use them.

Drying and Storing Onions

Once harvested, storing onion bulbs becomes necessary. Onions must first be dried before they can be stored. To dry onions, spread them out on a clean and dry surface in a well-ventilated location, such as a garage or a shed.

Cure onions for at least two to three weeks or until the tops necks are completely dry and the outer skin on the onion becomes slightly crisp. Cut tops off to within one inch (2.5 cm.) after drying is complete.

Store dried onions in a wire basket, crate or nylon bag in a place where the temperature is between 32 to 40 F. (0-4 C.). Humidity levels should be between 65 and 70 percent for best results. If the location is too damp, rotting may occur. Most onions can keep for up to three months if dried and stored properly.

What is Puccinia allii? It's a fungal disease of plants in the Allium family, which includes leeks, garlic, and onions, among others. The disease initially infects the foliar tissue and can result in stunted bulb formation if the plants are heavily infested. Also known as garlic rust disease, preventing puccinia allii rust can enhance your Allium crop.

Will Rust Disease Kill Onions?

First, the gardener must know what is puccinia allii and how to recognize it. The fungus overwinters in plant material and is most destructive in regions with heavy rain and fog. Over irrigating can also promote the formation of the spores that cause the fungal disease. The fungus appears as white to yellowish spots on the foliage and enlarge as the disease progresses. The spots become orange and they develop into black lesions over time.

So will rust disease kill onions and other alliums? In some field crops the fungus has caused dramatic losses and reduced yields. For the most part, garlic rust disease reduces plant vigor and size of bulbs. The disease is contagious and passes from plant to plant, as the spores are splashed onto neighboring foliage or are air borne through the crop.

Preventing Puccinia Allii Rust

There is a saying, “prevention is half the cure,” which is apt for most crop disease situations. Once the crop has garlic rust disease, you need to resort to chemicals for a cure. It's much easier and less toxic to prevent the formation of the spores in the first place. Since the fungus overwinters on other plant material, clean up dead plants at the end of the season. Rotate your allium crops to areas that were not previously hosting plants in the family. Remove wild forms of allium, which can also host the fungal spores. Don't water overhead and water in the morning. This gives foliage time to dry off quickly before the excess moisture can force a bloom of the fungal spores. There are no resistant varieties of Allium species.

Allium Rust Treatment

Once you have the disease on your plants, there are several chemical treatments that can combat the fungus. Fungicides must be labeled for use on edible plants and specify usefulness against puccinia allii rust. Always follow the directions and use with proper safety precautions. Fungicides should not be used within seven days of harvest. The best time to treat is before you see the spores. This may seem silly but effectiveness of fungicides is reduced when the plant is obviously infected and spores are in full bloom. If you've had problems with orange onion leaves or spotted foliage, then you can be sure you have the disease in your garden. Every season apply a preventative fungicide to the crop leaves.

Cultural Control of Garlic Rust Disease

Plants that are not stressed seem to tolerate small infestations of the fungus. Apply bulb fertilizer in early spring and keep the plants moderately moist. Plants with heavy layers of mulch may contract the disease from the soggy organic material. Pull away the mulch from just around the forming bulbs as the season progresses.

Onions are easy to grow and produce a tidy, reliable crop with very little effort, but storing onions properly is what allows that harvest to last. Once you understand the basics of how to harvest onions at the right time and handle bulbs carefully, learning how to store onions correctly will keep them usable for months. From planning and care in the garden – including how to grow onions successfully – good practices at every stage are rewarded with homegrown onions you can enjoy well into winter, even when snow covers the ground and nothing fresh is growing outside.

Store Fresh Green Onions

Spring onions and green onions won't store long. They can hold in the refrigerator crisper for a week or possibly more, but are best when they're fresh. These onions are used for their stems as much as the ends. The stems must be kept green and crisp for the best taste. Store green onions that still have their roots in 1/4-inch (6 ml.) of water in the refrigerator to keep the onions fresh longer. Change the water daily to prevent bacteria.

How to Keep Onions

You may wonder how to keep onions so they last well into the cold winter months. The bulbs are hardy and keep well if they are harvested at the right time and hardened off. The proper time to dig them up is when the sprouts have died back. Then, onions need to be cured.

Curing dries the outer skins of the bulb so it won't be as prone to rot and mold. Spread the onions in a single layer on a clean, dry surface. Let them dry for two or three weeks until the necks are dry and the skin is papery.

After they are cured, storing onions can be done in a couple of different ways. Cut off the tops or necks of the onions after they are cured. Discard any that show signs of decay or have soft spots. Use any bulbs that have thick necks first because they are more moist and don't store as well.

A fun way of storing onions is to put them in an old nylon stocking. Make knots between each bulb and hang the nylon. This keeps air circulation flowing and you can just cut a knot off as you need a vegetable.

Another method of storing garden onions is to set them in a basket or crate. Any container will do as long as there is airflow.

Best Conditions for Storing Garden Onions

All produce keeps best in cooler conditions, which slow down the decay process. Onions should be kept where temperatures are 32 to 40 F. (0-4 C.). An unheated basement or garage is suitable as long as temperatures don't freeze inside. The location must also be dry and low in humidity to prevent rot and molds.

The length of time you can store onions will depend on the onion variety and site conditions. Some bulbs can be stored for several months.

If your onion tops curl up, you may have a case of onion thrips. In addition to affecting gardeners growing onions, however, these pests have also been known to go after other crops including:

• broccoli
• cauliflower
• cabbage
• beans
• carrots
• cucumbers
• tomatoes
• squash
• turnips
• garlic
• leeks

You may also find thrips feeding on melons and some types of flowers. These insects are most active during spring but continue their damage throughout fall before overwintering in nearby debris.

Onion Thrips Damage

The trail of damage left by these pests can be easily seen as they can literally suck the life right of the plants. Typically, thrips prefer to feed on plant tissue from newly emerging leaves. Besides curling onion leaves, these insects produce silver or white-looking streaks on foliage. The young leaves appear distorted, and severely injured leaves may even turn brown and die. Bulb growth may be affected as well, being much smaller in size and deformed.

Controlling Thrips on Onions

While overhead watering, as well as rain, can help reduce their numbers, other controls are often necessary. Biological control of onion thrips generally includes the introduction of the pest's natural enemies such as minute pirate bugs, predatory thrips species, and lacewings. Unfortunately, these are only effective with small numbers of thrips, and they are also susceptible to most insect sprays.

Although damage from thrips on onions is most prevalent during early bulbing, it is highly recommended that these pests be controlled well before this. Otherwise, their populations may become large and more difficult to control.

You can evaluate these numbers by counting them on random plants throughout the garden. Pull the leaves apart and check under the leaf folds as well as near the base of the bulb. The nymphs can be recognized by their pale-yellow color while the winged adults will be light to dark brown. Having at least 15 to 30 of these insects means additional control is needed.

Most can be killed off with various insecticides, but contact-residual types or neem oil are more effective. Be sure to thoroughly coat the plant in order to compensate for the shape of the onion leaves.

There's nothing like the flavor of an onion fresh from the garden. Whether it's the narrow green ones in your salad or the fat, juicy slice on your burger, onions straight from the garden are something to behold. When they find that special variety that is particularly appealing, many gardeners want to know how to collect onion seeds for future sowing.

Once you have learned how to grow onions, then you'll find that harvesting onion seeds is a fairly simple process. Whether it's a preference for organically grown produce, economic considerations, or just the good feeling you get from serving food you've grown yourself, there's a renewed interest in collecting seeds to grow. People are searching the net for the richness and flavor of old-time varieties, and learning about saving seed for the next garden generation. Collecting onion seeds for future production can be your contribution to the process.

Collecting Onion Seeds from the Right Plants

Before we talk about how to harvest onion seeds, we need to say a few words about what kind of onions you can harvest onion seed from. Many of the seeds or sets acquired from large seed production companies are hybrids, which means the seeds are a cross between two parent varieties chosen for specific characteristics. When blended together, they give us the best of both varieties.

That's great, but if you're planning to harvest onion seed from these hybrids, there's a catch. The saved seeds will most likely produce onion with the traits of one parent or the other, but not both, and that's if they germinate at all. So, rule number one: Don't harvest onion seeds from hybrids.

The next thing you need to know about collecting onion seed is that onions are biennial. Biennials only bloom and produce seed during their second year. Depending on where you live, this may add a few steps to your list of steps.

If your ground freezes during the winter, a how to collect onion seeds list will include pulling the bulbs you have chosen for seed from the ground and storing them over the winter to be replanted again in the spring. They'll need to be kept cool at 45 to 55 degrees F. (7-13 C.). This isn't just for storage purposes; it's a process called vernalization. The bulb needs cold storage for at least four weeks to trigger the growth of scapes or stalks.

Replant your bulbs in early spring when the ground has warmed to 55 degrees F. (13 C.). After leaf growth is complete, each plant will send up one or more stalks for flowering. Like all allium species, onions produce balls covered with tiny flowers ready for pollination. Self-pollination is usual, but cross pollination can occur and in some cases should be encouraged.

How to Harvest Onion Seeds

You'll know it's time for harvesting onion seeds when the umbrels or flowering heads begin turning brown. Carefully clip the stalks a few inches (8 cm.) below the head and place them in a paper bag. Set the bag in a cool, dry place for several weeks. When the heads are completely dry, shake them vigorously within the bag to release the seeds. Keep your seeds cool and dry through the winter.

While most people know that scallions are simply young, immature onions and are easy to grow, not everyone is certain about when or how to harvest them. If you’re growing scallions, you’ll know they’re prized for their tender greens and small white stems, both of which can be harvested and used fresh or cooked. The greens and white stalks can be sliced or chopped into salads, used as a garnish, or added to cooked dishes, and they’re often used as a substitute for chives. In fact, a mature scallion looks very similar to a large chive and shares many of the same culinary uses. For gardeners already comfortable with growing onions, growing and harvesting scallions is a simple and rewarding variation.

When to Pick Scallions

Scallions are typically harvested prior to the formation of the onion bulb. Generally, the younger the scallion, the milder the flavor. The exact time for scallion picking varies upon personal preference but is usually within about 60 days after planting.

Scallions can be harvested several times throughout the season depending on their level of maturity, with most people harvesting them once they are at least a half inch (1 cm.) thick or anywhere from 8 to 12 inches (20-30.5 cm.) tall. Another way to tell their maturity is color. Scallions should be green, upright, and succulent whereas onions are ready for picking once they've turned yellow and flop over.

How Do You Harvest Scallions?

Once scallions are ready to be harvested, gently loosen the surrounding soil so you can carefully pull them up. When harvesting scallions, choose the largest and use them first, as it is best to both harvest and use scallions right away. Scallions left for too long will quickly wilt and lose their freshness.

However, if you are unable to use all of your harvested scallions, they may be stored in the refrigerator for up to one week. It's best not to wash them if storing is necessary. Keep the scallions in an airtight, plastic bag. Some people find placing them in a damp paper towel works as well.

When preparing scallions, be sure to trim off the roots and tip of the white stem as well as the top 2 inches (5 cm.) of greenery.

Onions, along with leeks, garlic, and chives, belong to the genus Allium. They come in various colors ranging from white to yellow to red, with a flavor range from mildly sweet to strongly pungent.

Onion bulbs develop in direct relationship to hours of daylight and are divided into two groups. Short-day cultivars produce the best bulbs when days are short and nights are long. Long-day cultivars produce during long days of sunlight when the nights are short. Long-day varieties tend to be more strongly flavored and store better.

The perfect onion will have 13 leaves and 13 rings of scales for each bulb. Learning how to grow onions is not difficult; however, even in perfect soil, nutrient, and light conditions, gardeners face a problem over which they have little control: onion bolting. Why does my onion plant have a flower so early? What is onion bolting? How can you keep onions from bolting?

Bolting is When an Onion Has Flower Buds

When an onion plant prematurely sends out a flower stalk, it's referred to as onion bolting. Onion bolting is a natural process that occurs when the plant is under stress. While we gardeners may enjoy the beauty and taste of our plants, we mustn't forget that the plant's sole purpose is to reproduce. When you notice your onion has flower buds, you know Mother Nature's whimsy has put the plant in panic mode – Help! Help! I'm going to die! The plant's genetically coded response is to reproduce as quickly as possible, and that means flowering! Now that you have the answer to, "What is onion bolting?", let's look at some of the causes.

What Causes Onion Bolting?

There are several possible reasons your onion has flower buds before it should. Since onions are planted early in the growing season, it's common in some areas to have a cold snap. Those few days of cold weather can send your more mature plants into panic mode – fall has arrived! I must see that my onion has flower buds before I die! A more common cause of onion bolting is the hot, dry weather of summer – my home has become an oven and I'm dying of thirst!

Do Not Let Onions Flower

So, how do you keep onions from bolting? Don't let onions flower! Protect your plants from those early-season cold snaps by covering them. Keep your plants well-watered during heat waves. Not only will your onions appreciate the drink, but the evaporation of surface water will also help cool the air around your plants.

The best way to keep onions from bolting is to keep them from stress. Not letting onions flower is often easier said than done, but there are a few things that might help. Use larger sets for green onions, and you'll harvest them before they have a chance to bolt. For larger onions, try seed or transplants, as studies show they acclimate better to temperature fluctuations.

As soon as you see an onion has flower buds, snip the buds to prevent the bulb from splitting, then harvest and eat those onions first, the sooner the better. Onions that have bolted don't store well. Onion bolting is a problem for even professional growers. You do what you can to prevent it and make the best of it when it happens anyway. A good thing for all gardeners to remember: You can't always beat Mother Nature.

Scallion plants are easy to grow and can be eaten as is, used as flavoring when cooking, or as an attractive garnish. Keep reading to learn how to plant this popular type of onion.

What are Scallions?

Scallions are produced from specific cultivars of the bulbing onion and have a mild flavor. Are scallions the same as green onions? Yes, they are commonly called green onions; however, these plants are actually a cross of the shallot.

Although sometimes marketed as such, the scallion is not the same as the leafy green top of the bulbing onion. It is the long, white shank that is used while the green part is often prepared as garnish. Regular onions do not produce this white shank. Furthermore, onion leaves are usually tougher and stronger tasting. Scallions are tender and mild.

So, what's the difference between shallots and scallions? While the two are often confused with one another, scallions (green onions) and shallots are quite different. The most distinguishing feature is found in the bulb. Shallots are made up of cloves, similar to garlic. Scallions have a bulb like that of a regular onion, only much smaller.

How to Grow Scallions

Growing scallions is actually easier than growing onions since they have a much shorter growth period. Varieties sown in spring can be harvested just 60 to 80 days (8-10 weeks) after planting or when transplants reach about a foot (31 cm.) tall.

Scallions need rich, well-draining soil. In addition, their shallow root systems require constant moisture and weed protection. Tightly packed plantings and mulch can not only help retain moisture but will keep weeds down too.

Shallow watering throughout the short growing season is also recommended.

How to Plant Scallions

Scallion plants can be sown four to eight weeks before transplanting outdoors or direct seeded in the garden four weeks before the last frost date in spring. Plant seeds about ¼ inch (6 mm.) deep, ½ inch (1 cm.) apart, and with 12 to 18 inches (31-46 cm.) of row spacing. Transplants or sets can be planted about an inch (2.5 cm.) deep with 2 to 3 inch (5-8 cm.) spacing. Blanch scallions as they grow by hilling up the soil.

Growing onions from seed is both easy and economical. They can be started indoors in flats and transplanted to the garden later or sow their seeds directly in the garden. If you know how to grow onions from seeds, either method for planting onion seeds will yield an abundant supply of onion crops. Read on to learn more about onion seed starting.

How to Grow Onions from Seeds

Onion seed starting is easy. It is best to grow onions in fertile, well-draining soil. This should also be worked with organic matter, such as compost. Onion seeds can be planted directly in the garden bed. However, when growing onion seed, some people prefer to start them indoors. 

This can be done in late autumn. The best time for planting onion seeds outdoors is in spring, as soon as the soil can be worked in your area. Place them about an inch (2.5 cm.) deep in the soil and approximately half an inch (1 cm.) or more apart. If planting rows, space them at least one and half to two feet (46-61 cm.) apart.

Onion Seed Germination

When it comes to onion seed germination, temperature plays an active role. While typically germination occurs within seven to ten days, soil temperature affects this process. For instance, the cooler the soil temperature, the longer it will take for onion seeds to germinate -- up to two weeks. Warm soil temperatures, on the other hand, can trigger onion seed germination in as little as four days.

Growing Onion Seed Plants

Once seedlings have sufficient leaf growth, thin them down to around 3 to4 inches (8-10 cm.) apart. Transplant onion seedlings that were started indoors about four to six weeks before the last expected frost or freeze date, provided the ground is not frozen. 

Onion plants have shallow roots and require frequent irrigation throughout the growing season. However, once the tops begin to lay over, usually by late summer, watering should be stopped. At this point, onions can be lifted. Growing onion seed plants is an easy, inexpensive way to keep an unlimited amount of onions on hand just when you need them.

People tend to think of onions as large-scale farm crops, probably because they’re such grocery store staples that they’re rarely seen in gardens. They’re actually quite easy to grow, and since they have shallow root systems and grow mostly aboveground, you can produce a massive harvest in a very small footprint and with very little soil.

In other words, they’re perfectly suited to container life! You can grow onions in containers on patios, balconies, and even indoors. The secret lies in finding the right onion variety for your climate, and in getting the soil just right. Below we’ll cover everything you need to know about growing onions in containers

How to Grow Onions in Containers

Growing onions in containers is very similar to growing them in the ground. You need good soil, adequate drainage, good fertilizer, and plenty of light. Really, the only thing you need to do differently is find the right container.

The Best Containers for Potted Onions

Container grown onions need very little soil depth, and several of them can be planted in the same container. You already have a good idea of how wide onions can grow, so you have a sense of the size of container you’ll need. An ideal onion container would be 10 inches (25 cm) deep, and several feet (at least 60 cm) across. A long trough-style planter like this one from Amazon is a good bet.

Potted onions also need extremely good drainage. Leave an onion sitting in soggy soil, and it’ll rot within days. A good option to ensure drainage is a trough-style fabric grow bag, like this one from Amazon.

There’s nothing that says you can’t grow onions in smaller containers. Just know that you’ll either have a small crop, or you’ll be planting in lots of pots.

Choosing the Best Location

As we covered above, onions need a whole lot of light to develop bulbs. Once it’s warm enough to move your containers outdoors, the sun ought to take care of that. If you’re starting onions indoors, however, or just growing them as an indoor crop, you’ll need supplemental lighting. A grow light like this one from Amazon should have you covered.

Which Type of Onion Should You Grow?

It’s important to choose a variety of onion that matches your zone. Otherwise you can wind up with lots of green leaves but tiny, disappointing bulbs.

Onions are photoperiodic, which means they’re affected by the number of hours of sunlight they get in a day. Until they reach a minimum number of hours of light in a day, they won’t start forming bulbs.

Different varieties of onions are classified according to the number of hours of light in a day (daylength) needed for onion bulb formation. There are three main groups:

• Short-day onions: These need at least 10-12 hours of daylength for bulbs to form. This usually falls around May or June. It’s best to plant them in the fall and let them overwinter. In the spring, bulbs will start to develop. Good for southern states (zone 7 and up).
• Intermediate/Day-Neutral Onions: These need 12-14 hours of daylength to start bulbing. Start them indoors in late winter, and they can be harvested in June to early July. They’ll grow pretty much anywhere.
• Long-Day Onions: These need 14-16 hours of daylength. They grow best in northern states (zone 6 and lower).

Ways to Start Onions

There are two different ways you can start growing onions. They both work perfectly fine in containers. Which you pick just depends on your skill level (or bravery) and how much time you have.

• Seeds: These are cheapest, but take a long time. You should start onion seeds indoors 8-10 weeks before the last frost date.
• Sets: These are seedlings, shipped in bundles. They tend to produce large, reliable bulbs, and are easier than seeds. Plant onion sets 1 inch (2.5 cm) deep 2-4 weeks before the last frost date.

Burpee offers several dozen varieties of onions as both seeds and sets.

Watering Potted Onions

While drainage is essential, so is moisture. It’s a tough needle to thread, I know. Onion soil should be kept consistently moist, like a wrung-out sponge. If the soil dries out completely, you run the risk of your onions bolting, which will ruin the bulb.

Container grown onions dry out faster than those grown in the ground. Check them daily, and if the top of the soil is dry to the touch, give them some water. Onions grown in containers will need at least 2 to 3 inches (5-8 cm) of water per week. If the weather’s dry, they’ll probably need more.

Perhaps you found a great early deal on onion sets, maybe you have grown your own sets for planting in the spring, or maybe you just didn't get around to planting them last season. Whatever the case, you need to store the onion sets until you're ready for planting onions in your garden. How to store onion sets is as easy as 1-2-3.

Storing Onion Sets - Step 1

Storing onion sets is much like storing plain old onions. Find a mesh type bag (like the bag your store-bought cooking onions come in) and place the onion sets inside the bag.

Storing Onion Sets - Step 2

Hang the mesh bag in a cool, dry place with good air circulation. Basements aren't ideal locations, as they tend to be damp, which can cause rot when storing onion sets. Instead, consider using a semi-heated or connected garage, an attic, or even an uninsulated closet.

Storing Onion Sets - Step 3

Check the onion sets in the bag regularly for any signs of rot or damage. If you find any sets that are starting to go bad, remove them immediately from the bag as they could cause the others to rot as well. In the spring, when you are ready for planting onion sets, your sets will be healthy and firm, ready to grow into nice, big onions. The question of how to store onion sets really is as easy as 1-2-3.