DibbleWhen to plant onion in Zone 6
In Zone 6, the last spring frost usually passes around April 21 and the first fall frost arrives around October 17, leaving about 179 frost-free days. The windows below are computed from those frost dates, with the same math the Dibble app uses.
Generous season. Spring and fall plantings both productive.
Planting windows for onion in Zone 6
| Task | Window |
|---|---|
| Start seeds indoors | Feb 10 to Feb 24 |
| Transplant | Apr 7 to Apr 21 |
| Estimated harvest | Jul 16 to Jul 30 |
The harvest estimate counts 100 days to maturity, then a picking window of about 14 days. These windows use typical frost dates for Zone 6; Dibble pins them to your exact ZIP code.
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How to grow onion
Start onion seeds indoors 10 weeks before last frost, or use sets. Transplant 2 weeks before last frost, onions are hardy and size up with cool early growth.
Companion plants
Good neighbors for Onion:
Better kept apart:
Onion in nearby zones
Keep exploring
Onion: the full growing guide · The Zone 6 planting calendar · Every crop and zone
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Dates are estimates based on typical frost dates for the zone. Your yard has its own microclimate, so use them as a starting point and adjust as you learn your space.