Onions come in two main categories -- bulbing and green. Bulb-type onions can be stored and are sometimes called storage onions. Green onions are the fresh eating onions and are referred to as bunching or multiplying onions.

Some varieties of bulb onions also don't have a long shelf life. These varieties include Bermuda, Ggranex 33 and Texas Grano 502 and 1012.

Onions can be planted by seed, onion sets or transplants, says Mary Beth Musgrove, a horticulturist with the Alabama Cooperative Extension System.

One disadvantage of planting sets is that there are no named varieties to choose from. Only yellow, white or red sets can be purchased. Fresh or sweet bulb onions are not available as sets.

Onions are easier to establish from transplants, says Musgrove. Bulb type onions can be transplanted in Alabama from December through February. Plant bulbs to a depth of 1 to 1 1/2 inches and 3 to 4 inches apart. They grow best in a 6.0 to 6.5 ph soil. Add several inches of organic matter and till the soil to a depth of 8 to 10 inches to make it loose and friable.

A good way to plant onions is in a raised bed. Onions should be dressed with nitrogen in mid-February and again about mid-March.

Bulbing onions transplanted in December or January mature in mid- to late May. When the tops of the onions begin to fall over, they are ready to take up with a spade shovel, says Musgrove. Don't take up onions too early, because most of their growth occurs in early May.

Green multiplying onions can be planted from seed in early spring and harvested in about 90 days. They can be divided and reset anytime from October to February and can be thinned and enjoyed throughout the fall and winter months. Good varieties include Evergreen White and Silver Skin.

Growing conditions can influence the flavor of onions. Onions planted in a soil with a high sulfur content will have a more pungent taste.

Plant short-day, bulb-type onion varieties such as Bermuda, Granex 33 or Texas Grano 502. These onions produce sweet, fresh bulbs when grown during months of short day length.