When to plant onion in Zone 11
In Zone 11, the last spring frost usually passes around January 1 and the first fall frost arrives around December 31, leaving about 365 frost-free days. The windows below are computed from those frost dates, with the same math the Dibble app uses.
Frost-free, tropical. Year-round growing; timing follows wet/dry and heat, not frost.
Planting windows for onion in Zone 11
| Task | Window |
|---|---|
| Start seeds indoors | Oct 23 to Nov 6 |
| Transplant | Dec 18 to Jan 1 |
| Estimated harvest | Mar 28 to Apr 11 |
The harvest estimate counts 100 days to maturity, then a picking window of about 14 days. These windows use typical frost dates for Zone 11; 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 11 planting calendar · Every crop and zone
Plant at the right time this season
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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.