DibbleWhen to plant broccoli in Zone 4
In Zone 4, the last spring frost usually passes around May 10 and the first fall frost arrives around September 21, leaving about 134 frost-free days. The windows below are computed from those frost dates, with the same math the Dibble app uses.
Cool climate with a brief warm window. Indoor starts and season extension help.
Planting windows for broccoli in Zone 4
| Task | Window |
|---|---|
| Start seeds indoors | Mar 29 to Apr 12 |
| Transplant | Apr 26 to May 10 |
| Estimated harvest | Jun 30 to Jul 21 |
The harvest estimate counts 65 days to maturity, then a picking window of about 21 days. These windows use typical frost dates for Zone 4; Dibble pins them to your exact ZIP code.
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How to grow broccoli
Start indoors 6 weeks before last frost; transplant 2 weeks before. Cut the central head, then enjoy side shoots for weeks.
Companion plants
Good neighbors for Broccoli:
Better kept apart:
Broccoli in nearby zones
Keep exploring
Broccoli: the full growing guide · The Zone 4 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.