Allium cepa, commonly known as the onion or bulb onion, is one of the most widely cultivated and economically important vegetable crops in the world. It is a biennial herbaceous plant belonging to the amaryllis family (Amaryllidaceae). Onion seeds germinate readily without dormancy at warm temperatures and are easy to grow from seed, making them ideal for home and commercial gardeners.
Before sowing
No pre-treatment needed — sow directly.
Onion seeds have no dormancy and do not require special pre-treatment before sowing
Sowing
What to expect
Tips
Sow indoors 8-10 weeks before the date of the last frost; seeds germinate fastest at 68-77°F (20-25°C) in darkness. Keep soil consistently moist but not waterlogged during germination. Use a heat mat to maintain warm soil temperatures for faster, more uniform germination. Cover seed trays with a propagation dome to retain moisture until germination occurs. Thin seedlings to prevent overcrowding and strengthen growth. Transplant seedlings outdoors when soil temperature reaches at least 50°F (10°C), avoiding exposure to prolonged temperatures below 50°F as this may cause bolting. Onion seeds are short-lived; store unused seed in cool (below 40°F/4°C), dry conditions to preserve viability for up to 3 years.
Sources: Seeds Savers Exchange, Johnny's Selected Seeds, Utah State University Extension, High Mowing Organic Seeds, Harvest to Table, International Seed Testing Association
