By Susan Patterson, Master Gardener
The use of onions for food goes back over 4,000 years. Onions are popular cool season vegetables that can be cultivated from seed, sets or transplants. Onions are an easy-to-grow and manage crop that, when properly harvested, can provide a kitchen staple through the fall and winter.
Success in Harvesting Onions
Your success in harvesting onions will depend on proper planting and care throughout the growing season. Plant onions as soon as the garden can be worked. Rich soil, consistent moisture and cool temperatures help bulb development. It is 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 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.
Bulb onion harvest time can begin with onion tops naturally fall over and brown. This is usually 100 to 120 days after planting, depending on the cultivar. Onion harvest time should be early in the morning when temperatures are not too hot.
How to Harvest Onions
Knowing how to harvest onions is also important, as you do not want to damage the plants or onion bulbs. Carefully pull or dig onions up from the ground with the tops intact. Gently shake the soil from around the bulbs.
Drying and Storing Onion Bulbs
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.
Onions should be cured 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 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 degrees F. 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.