How Often Should You Fertilize Your Lawn?

By: Gardening Know How Picks

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When it comes to fertilizer, more isn’t necessarily better. While proper application of fertilizer can keep your lawn looking green and lush throughout much of the year, you can end up wasting time and money if you over-fertilize — and in some cases, you can even harm the very grass you’re trying to feed.

You need to know when to fertilize, but also how much to use and how to apply it. If you don’t have the time to put into fertilizing your lawn on a regular basis, consider hiring a professional lawn service to take care of it for you. We recommend TruGreen, a nationwide provider of lawn maintenance services with many years in the business and a great reputation. 

To get a free estimate for your lawn call 877-386-6512 or fill out the quick and easy form on the company’s website.

In This Article:

  • What is Lawn Fertilization? 
  • How Often Should I Fertilize My Lawn? 
  • When Should I Fertilize My Lawn?
  • Why Professional Lawn Fertilization May Be Right for You
  • How Much Does Lawn Fertilization Cost? 
  • Top Recommended National Provider: TruGreen 
  • Frequently Asked Questions 

What is Lawn Fertilization? 

Fertilizing a lawn is the process of applying material that will provide additional nutrients for the turfgrasses and other plants growing there. Most commercially available fertilizers supply various amounts of nitrogen, phosphorus, and potassium that work their way down into the soil for plants to absorb through their roots. Some fertilizers also contain minerals like calcium or magnesium to help grass grow.

In the wild, soil constantly gets its nutrients replenished through the life cycle of plants — they absorb nutrients to live, and when they die, the nutrients in their decomposing matter return to the soil for the next generation of plants to use. However, few homeowners want a yard full of dead plants while they wait for the soil to recharge. To maintain healthy grass for an entire growing season, the soil usually needs some extra help in the form of fertilizer.

Of course, one look in a hardware store will let tell you that there are many types of fertilizer available that come in a variety of different strengths. Which product is best for your lawn will depend on the climate where you live and the types of grasses you want to grow, but there are some important characteristics of a good fertilizer to look for.

Slow-Release vs. Quick-Release Fertilizer

A fertilizer’s release time is how long it will continue to provide nutrients for the soil. As the name suggests, quick-release fertilizer dumps large amounts of nutrients into the soil immediately, making for fast and impressive grass growth. This might be helpful if, for example, you’re hosting a special event in the backyard and you need grass coverage fast. 

However, in the long run, overuse of quick-release fertilizers can harm the soil quality. For long-lasting, healthy grass, you’ll want to stick to slow-release fertilizers as much as possible. These take longer to work, but their results last longer as well. 

Synthetic vs. Organic Fertilizer

All fertilizers contain some combination of nitrogen, phosphorus, and potassium. However, some of those nutrients come from natural sources while others don’t. Synthetic fertilizers contain little else but concentrated amounts of these nutrients that were created in a lab. A little bit of synthetic fertilizer goes a long way, and using too much may burn your plants’ leaves and stems. These fertilizers also dissolve in water, meaning they end up in runoff and can get into water sources.

Organic or natural fertilizers, on the other hand, are derived from plant or animal sources like compost, manure, or seed meal. They contain smaller amounts of nutrients, but the other natural materials in the mix can help improve the texture and structure of the soil. Additionally, it is more difficult to over-fertilize with organic products, as they are by nature slow to release their nutrients.

In contrast, synthetic fertilizers are usually quick-release. It is possible to buy slow-release artificial fertilizer, but it’s usually more expensive. For healthier plants with robust roots, it’s usually best to stick to organic, slow-release fertilizers.

Granular vs. Liquid Fertilizer

While the consistency of the fertilizer isn’t as important as its release time and organic content, there are still some factors to consider. Organic fertilizers come in the form in which they can best be stored, so fertilizers like corn grain meal and blood meal are granular, and fertilizers like fish emulsion are liquid. Synthetic fertilizer usually comes in granular form, but liquid is available, too.

Put simply, granular fertilizer is easier to apply to a large surface area like a lawn, though you’ll want to invest in a spreader to make sure it goes on evenly. Liquid fertilizer usually limits you to the reach of your hose, and even a small amount of wind can trick you into accidentally over- or under-fertilizing a given area. In general, it’s best to leave liquid fertilizer to the pros with the right training and equipment to apply it properly.

NPK Values

Any packaged fertilizer should show a series of three numbers that show the ratio of nitrogen (N), phosphorus (P), and potassium (K) it contains. This is called its NPK value, and it should be printed on the label in a XX-XX-XX format. For example, a fertilizer with a 20-5-5 value contains 20% nitrogen, 5% phosphorus, and 5% potassium — four times as much nitrogen as phosphorus and potassium. A 10-10-10 fertilizer has equal amounts of all three nutrients, but is only half as concentrated as a 20-20-20 fertilizer.

Nitrogen, phosphorus, and potassium all serve different functions for plants, and for the purposes of grass growth, nitrogen is the most important of the three. The University of Illinois recommends a fertilizer with a 3:1:2 or 4:1:2 ratio to best feed your lawn. That could mean an NPK value of 15-5-10 or 20-5-10. Ensure that the product you’re using has three or four parts nitrogen to one part phosphorus to two parts potassium.

To sum up: although synthetic, quick-release fertilizers can be handy in a pinch, you’ll typically want to use organic, slow-release, granular fertilizer with a 3:1:2 NPK value to keep your lawn looking its best.

How Often Should I Fertilize My Lawn?

For most types of grass in most climates, fertilizing once or twice a year is plenty. If you decide to do it yourself, the fertilizer container you buy should have instructions regarding how often to use the product. If you hire a professional service, you can discuss your options with the lawn care technician. They should be able to help you set up a schedule to determine how often to fertilize your lawn.

A good slow-release fertilizer should last at least six to eight weeks, so be sure not to overdo it. Quick-release fertilizers can be used every four weeks, but the high concentration of salts in these fertilizers makes it more likely that they will chemically burn your plants. Additionally, plants and soil can only hold so many nutrients at one time, so you’ll be wasting fertilizer.

When Should I Fertilize My Lawn? 

The answer to this question is a bit more complicated and depends on whether you’re trying to grow cool season or warm season grasses. Cool season grasses like Kentucky bluegrass, perennial ryegrass, and fescue grow best in the northern part of the US and should be fertilized in fall. They do most of their growing during the winter months, so be sure to fertilize cool season grasses before the cold weather hits. If necessary, you can apply fertilizer again in the late spring.

On the other hand, warm season grasses grow best in warm climates and go dormant in winter. Species like Bermuda grass and St. Augustine grass should be fertilized in early or late summer, but not at the very peak of hot weather. If you’re in the transition zone where both cool season and warm season grasses can grow, do some research on the species of grass or talk to a lawn care professional.

It’s important to choose the right time of year to fertilize, but it’s also important to choose the right time of day. Always avoid fertilizing in the midday heat to reduce the stress on your grass and other plants. In general, morning is the best time, since wind and temperatures are lower. Read the directions that come with the product to determine when to water your lawn, and remember that most granular fertilizers require water to activate. Some also require you to water for several days ahead of time, and you’ll generally want to mow your lawn before fertilizing it. Leaving some grass clippings behind can help boost the fertilizer, since these clippings are full of nitrogen.

Why Professional Lawn Fertilization May Be Right for You

Although fertilizing your lawn is a job you can certainly take on by yourself, hiring a professional lawn maintenance service often makes sense. This will save you time and effort, of course, and you’ll also get the benefit of expertise. Professionals have the experience necessary to apply the right amount of fertilizer evenly every time. They should also be able to analyze your soil and plants to determine what kind of fertilizer you need and how often you need it.

If you want to hire a professional, the first step will be deciding whether to employ a local service or a nationwide company. Both have their respective benefits and drawbacks, but nationwide companies are generally more accessible and have the resources to offer their services at lower prices. They also tend to have more personnel at hand who have the benefit of standard training.

How Much Does Lawn Fertilization Service Cost?  

There’s no standard cost for lawn fertilization because there’s no standard lawn. Lawn companies tend to base their prices on the following factors:

  • The size of your lawn — Larger lawns (that is, over 5,000 square feet) will usually cost more per treatment than smaller lawns.
  • Your geographical location — Costs will be higher where the general cost of living is greater and where grass is more difficult to grow.
  • The condition of your lawn — A lawn that is mostly healthy to begin with won’t require as many treatments as one that starts off in poor condition.
  • The species of grass or plants — If the grass you have your heart set on doesn’t grow well in your climate, your lawn will probably require more fertilizing.

In general, however, professional fertilizing services tend to cost between three and five cents per square foot, according to HowMuch.net, meaning that a 5,000 sq. ft. yard will cost $150-$250, including labor. However, some companies will offer lower prices if you bundle fertilizer treatment into an annual lawn care package.

Top Recommended National Provider: TruGreen

If you choose to go with a nationwide service, we recommend TruGreen, a lawn care company that’s been in business for 50 years and is available in every US state except for Alaska and Hawaii. It’s accredited by the Better Business Bureau and boasts an A+ rating.

To get an estimate, call 877-386-6512. You can also fill out an easy online form and get 50% off your first application. 

Read our review of TruGreen for more information.

While TruGreen’s prices will vary based on your yard and location, in many areas, the first fertilizer treatment is available for only $29.95. TruGreen also offers five annual lawn care plans that encompass a number of other services, including aeration, weed control, tree and shrub care, and lime amendment. Their TruNatural plan uses only natural, organic fertilizers.

Frequently Asked Questions

Can you over-fertilize your lawn? 

Yes, it’s possible to apply too much fertilizer or apply it too often, particularly if you’re using a synthetic, quick-release fertilizer. The high concentration of salts in these products can chemically burn leaves and stems, potentially killing the plants you’re trying to feed. To avoid this, make sure you use the proper amount of fertilizer — as recommended on the product’s packaging — and spread it evenly.

If you apply fertilizer too often, even if you spread it evenly, you can end up lowering the quality of the soil in the long run. Quick-release fertilizers only contain nutrients that plants can uptake quickly; they don’t have micronutrients to support healthy bacteria and fungi in the soil. To keep the soil healthy, use organic, slow-release fertilizers that will enrich the soil for the long-term health of your lawn.

How long do you have to wait between fertilizer applications? 

You generally don’t need to fertilize more than a few times a year, but if you want to apply fertilizer more frequently, wait at least six to eight weeks between applications. If you fertilize more often than that, you could end up damaging the plants or simply wasting fertilizer, since the soil can only hold so many nutrients.

Should I fertilize my lawn in the summer? 

No matter what kind of grass you have, avoid fertilizing in the hottest part of the summer. Plants experience stress under intense heat, and you may end up losing fertilizer to evaporation, anyway. If your lawn consists of warm season grasses, apply fertilizer in the early or late summer when the days aren’t quite as hot. Cool season grasses, however, should be fertilized in the fall.

How can I thicken my lawn?

If your lawn is looking thin and patchy, fertilizer can certainly help, but for best results, use it as part of a broader system of lawn maintenance. Here are some steps to take to maintain a full and healthy lawn.

  • Mow your lawn regularly. 
  • Water irregularly but deeply to promote strong root growth.
  • At least once a year, aerate the soil using a garden fork or plug aerator.
  • If you want to add more seeds, do so after aerating. Spread the seeds evenly and water immediately after sowing them.
  • Fertilize the grass once or twice a year with a slow-release, organic fertilizer.
  • Keep an eye out for weeds and remove any infestations as soon as possible.
  • Examine any bare or discolored patches for signs of disease or insects. Have these treated immediately if they occur.

If you’d like assistance with any of these steps, consider hiring a professional lawn service like TruGreen to help you keep up with regular maintenance and prevent problems before they occur.

Can dead grass come back to life? 

If the grass is actually dead, there’s no reviving it. However, just because your grass is brown, that doesn’t mean it’s dead. In times of drought, most grasses can go dormant for four to six weeks before they truly begin to die. Dormant grass should come back to life after a few weeks of watering.

Brown, dead-looking spots in an otherwise healthy lawn can be signs of disease, insect infestation, or harmful fungus. These areas will need to be treated, and they may ultimately need reseeding to become healthy again.

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