Onion Growing Info

Learning Download: How to Grow Onions

When to Plant:

Direct sow seeds as soon as the soil can be worked in the spring. Onion seeds can be started indoors 3-4 weeks before soil can be worked.
Bulbing onions are dependent on day length for bulb production; short-day onions produce bulbs when they receive 11-12 hours of daylight are best for Southern states, long-day onions need 14-16 hours are best for Northernstates.

Use a 10-5-5 fertilizer or something similar. Onions like a lot of Nitrogen.

Location:Planting Depth:Soil Type:
Full Sun1/8-1/4″Well drained,fertile soil, pH 6.2-6.8
Seed SpacingRow SpacingSeeds per 100′Yield per 100′Seeds per Acre
Onion3-6″12-18′400100 lbs.175,000


Onion Seeds:

1 Ounce: 7,500 Seeds
1/8 Pound: 15,000 Seeds
1/4 Pound: 30,000 Seeds
1/2 Pound: 60,000 Seeds

1 Pound: 120,000 Seeds

* These are average onion seed counts.  Varieties can vary.

Space Conversion:

1 Acre = 43,560 square feet, or 435’x100′
Weight Conversion:
1 Pound = 16 Ounces
1 Ounce = 28.4 Grams