Ohio sweet on onions
Are you surprised like I am to learn that onions are the most popular vegetable in Ohio home gardens?
The onion plant (Allium cepa), also known as the bulb onion or common onion, is the most widely cultivated species of the genus Allium. Garlics, leeks, shallots and chives are related to onions and all belong to the family Alliaceae.
There are three ways to grow onions: seeds, sets or transplants.
Growing onions from seeds is the least expensive method but requires the most work. Onion seeds planted indoors in early spring can take four to six weeks to be ready to plant outdoors. Onion seeds can be planted directly in workable soil in April, sowing a half-inch deep.
Most home gardeners plant onion sets in spring. These are dormant bulbs that are planted into the ground. These are readily available in garden centers or can be ordered by catalog. Plant onion sets 1 to 2 inches deep and 2 to 3 inches apart. As the onions grow, they can be thinned and used as green onions.
The last way to plant onions is from transplants, which again can be purchased at your local garden center. This allows you to choose specific varieties of onions. These plants are a little more expensive than sets.
For planting these, it is suggested to bury the roots and 1 inch of the lower part of the plant. You still can plant and get size if plants are well tended. Fall planting is for perennial of multiplier types.
Onions love well-drained, fertile soil with a pH level of 6.0 to 6.8. There is still time to get your soil tested this season to be sure you are meeting the needs of your vegetables. For a soil test, call OSU Extension Mahoning County at 330-533-5538 or Trumbull County at 330-638-6783.
For disease management, avoid planting onions in the same location year after year and space them appropriately in well-drained soil. Rotating the onion planting and avoiding undecomposed materials (i.e., manure) prevents onion maggots, the larvae of a small fly that feeds on onion roots. If applying fresh manure, do it in fall for best results.
Some types of onion cultivars grown in Ohio are green — ideal for bunching (Ebenzer); dry – ideal for storage (Walla Walla); and sweet from plants (white and yellow sweet Spanish).
Harvest green onions when tops are 6 inches tall. Bulb onions can be harvested when two-thirds of the dried tops have fallen over. Once pulled, they can be laid out in the sun to dry for several days and then cured in a well-ventilated attic or porch out of sun for one to two weeks. Store onions in very cool (32 to 40 degrees), dry conditions for up to six to seven months.
To learn more about onion diseases and onion cultivars that grow well in Ohio, go to go.osu.edu/onions.