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Plant Detail

Onion

Scientific name	Allium cepa
Common name	Onion
Type	Vegetables
Variety	Perennial
USDA Zone hardiness	2a - 10a
Exposure	Full sun
Height	Under 1'
Spread	Under 1'

The Onion is a cool-season vegetable that can be grown throughout most of North America. Onions may be grown from sets, transplants or seeds. Onions start bulb formation when the day length is just right, different varieties of onions require different day lengths to develop. Most varieties fall into one of two classes, long-day best suited for northern latitudes and short-day for southern latitudes. To produce green onions, plant the larger sets 1 inch deep and close enough to touch one another. Green onions should be harvested before crowding becomes a problem and bulbs begin to develop (Anytime after the green shoots are 6 inches). To produce dry onions, plant the smaller sets 1 inch deep, with 2 to 4 inches between sets. Onions are ready to harvest once the stalks begin to fall over, harvest and use any onion that flowers. Once they set flower they will not store long. Onions do not compete well with weeds so keep your garden managed.