Onions planting calendar
When to plant onions — pick your state
Onions timing swings hard by climate — choose your state for sow, transplant, and harvest dates calibrated to its USDA zone and frost window.
Northeast
Southeast
Midwest
Southwest
West
Pacific
Not listed: Hawaii — the dominant climate zone there is outside onions's practical range, so a generic calendar would mislead more than it helps.
Common questions
When should I plant onions?
Onions are day-length sensitive: long-day varieties (zones 1–6) begin bulbing when days exceed 14 hours, short-day types (zones 7–10) bulb at 10–12 hours, and intermediate-day varieties span zones 5–6. Start seeds indoors 10–12 weeks before the last spring frost and transplant out 4–6 weeks before it — young onion seedlings tolerate frost down to about -6 °C once hardened off. In zones 8–10 a second planting from sets in autumn is common, overwintering for an early-summer harvest. Because the right window depends on your local frost dates, pick your US state above for a calendar with exact sow, transplant, and harvest dates.
Does the best time to plant onions vary by state?
Yes — planting dates swing by several weeks across the US because each state sits in a different USDA zone with its own frost window. Every state page here gives onions dates calibrated to that state's climate.
How are these onions planting dates calculated?
Each state's dates come from that state's dominant USDA hardiness zone and NOAA average frost dates, then adjusted for onions's cold tolerance and days to maturity.