Growing Onions in Your Backyard

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The business of a new year is an excellent time to sort through seed catalogs and make your wish list for this year’s garden. Onions grow best during cool weather and are usually planted in the fall. But, do not cross them off the list just yet, there is still time.

Gardeners should target  now through March for setting out bulb onions and February though March for planting green onions. If you are setting out transplants, they should be planted in the early spring for best results.

Planting in a raised bed or garden row will help with drainage and it will make harvest a little easier. Gardeners may want to add organic matter to the garden soil to help prevent compaction. Typically, our soil has a clay texture to it and benefits from amending with organic matter.

There are several options when selecting onions to plant. You may plant onions from sets, seed, or transplants. There are pros and cons to each. Onion sets are small, dry onion bulbs that have been grown the previous season but were not allowed to mature. They can be pricey, and they do not make the best bulbs. Sets are also more susceptible to cold or freeze injury. When selecting sets, avoid those that are larger than an inch in diameter. These are more likely to bolt. Onions sets should be planted 1 1/2 inches deep. Onion seeds may be direct seeded within 1/2 inch of the soil. Gardeners may need to thin after they germinate. Onion transplants should be half the thickness of a lead pencil at the time of transplanting. The bottom of the transplant should be planted about 1-1 1/2 inches below the surface of the soil. The transplants should be spaced 3 to 4 inches apart in the row. All onions may be planted in rows 1 to 2 feet apart in a moist seedbed.

Before selecting an onion variety, think about how it grows. The growth of the onion is in response to day-length. When the number of daylight hours reach a certain level, onion plants start forming bulbs. Long-day onions need about 14 to 15 hours of daylight to bulb. Short-day onions need 10 hours of daylight. Day-neutral onions form bulbs regardless of daylight hours and produce well in almost any region. As soon as day-length hits the 10-hour mark, a short-day onion starts forming a bulb. If the top of the plant hasn’t had enough time to grow big and lush, the resulting bulb will be small. If day-length never hits 14 hours, long-day onions will never form a bulb. There will only be green leaves. In our area, gardeners will have greater success with short-day onions, since summer days do not vary as much in length from winter days. Day-neutral onions develop bulbs in any region and would be another option for gardeners here.

Short-day varieties have a mild, sweet flavor and are best eaten fresh. They do not store well. Proven varieties for our area include Georgia Sweet, Sweet Red, Texas Super Sweet, and Texas Sweet White. For the only day-neutral variety there is one that stands above the rest, Candy. The flavor just can not be beat.

Written By

Joanna Radford, N.C. Cooperative ExtensionJoanna RadfordExtension Agent, Agriculture and Natural Resources Call Joanna E-mail Joanna N.C. Cooperative Extension, Surry County Center
Updated on Jan 11, 2021
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