Growing Onions

Organic Vegetable Gardening
Fact Sheet

Botanical name: Allium cepa



Planting time: SP,FA
Seeds per ounce: 8000
Ounces per square foot: .002
Minimum legal germination rate: 70%
Germination type: Short Germinating seeds

Growing Onions in your garden is easy and it's one of the most important vegetables in the world.

For beginners, tyur most success will come from starting onions sets, but growing from seeds in flats easy, but requires more patience. Onions can be used as green onions within 30 days if grown from sets; or 40 to 50 days if grown from seed.

Important Day-Length Information

Globe (bulb) onions are one of those vegetable species that are day-length sensitive (or night-length), and the increased bulb growth (not leaves) responds to the length of the day. There are three types of onions and knowing where you live, and what type of onions to grow is important.

  • Long Day Onions(LD): grow where the day length is 14 to 16 hours long
  • Short Day Onions(SD): grow where the day length is 11 to 14 hours long
  • Day-Neutral Onions(DN): not affected by day length

Onions are very adaptable when it comes to climate and are frost tolerant. Onions will perform better in cooler weather. A constant supply of moisture ensures success with Onions.

Onions, as members of the allium family, are cousins of Garlic, Leeks, and Bunching Onions. They're biennials (grows for two years), growing the first year then blooming the second.


In garden spacing (inches): 4
In flat spacing (inches): Broadcast
Planting depth (inches): Cover seed with soil.
Maximum number of plants per square foot: 13
Nutrient relationship:: Light Feeder


Days to maturity: 98-119
Harvesting period (days): -
Minimum yields in pounds /square foot: 1


Diseases: Botrytis Leaf Blight, Damping-Off, Downy Mildew, Fusarium Basal Rot, Neck Rot, Onion Smut, Pink Root, Purple Blotch, Several Bacteria, White Rot
Insect pests:(Insect Pest Finder) Army Cutworm, Cutworm, Green Peach Aphid, Greenhouse Whitefly, Leafminer, Northern Mole Cricket, Onion Eelworm, Onion Maggot, Onion Thrips, Saltmarsh Caterpillar, Slugs and Snails, Spotted Cucumber Beetle, Striped Cucumber Beetle, Vegetable Weevil


Ailsa Craig (LD), Australian Brown (ND), Borettana Yellow (LD), Red Wethersfield (SD), Yellow Ebenezer (LD), Yellow of Parma (LD), Yellow Sweet Spanish (LD), Walla Walla (DN), Yellow Bermuda (SD), White Creole (SD), Red Grano (SD)


Organic Gardening Seed and Plant Sources:



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