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Can You Grow Onion in Illinois?

US · USDA Zone 5b · zones 4a, 4b, 5a, 5b, 6a

Grows well here

Onions grow well here — plant sets or transplants in early spring for a summer harvest.

Plant zones

2a–9b

Illinois last frost

early April

Illinois first frost

late October

Days to harvest

90–120 days

When to plant Onions in Illinois

Start indoors

Feb 9

Transplant

Apr 7

Harvest

Jul 6 – Aug 5

Dates are approximate, based on Illinois's average frost dates. Your exact yard may vary by microclimate.

About Onion

Onions are a staple crop that stores well and can be grown as sets transplants or from seed.

Growing from sets is easiest for beginners. Plant in early spring — onions are frost-tolerant. Day-length sensitive — choose short-day long-day or day-neutral varieties based on your latitude.

Full onion growing guide →

Gardening in Illinois

Illinois has a humid continental climate with hot summers and cold winters. Chicago is Zone 5b-6a; southern Illinois is warmer at Zone 6-7. Classic Midwest growing region.