DibbleWhen to plant sunflowers in Zone 9
In Zone 9, the last spring frost usually passes around March 1 and the first fall frost arrives around December 1, leaving about 275 frost-free days. The windows below are computed from those frost dates, with the same math the Dibble app uses.
Very long season. Plant cool crops in fall and winter; manage summer heat.
Planting windows for sunflowers in Zone 9
| Task | Window |
|---|---|
| Direct sow | Mar 1 to Mar 15 |
| Estimated harvest | May 20 to Jun 10 |
The harvest estimate counts 80 days to maturity, then a picking window of about 21 days. These windows use typical frost dates for Zone 9; Dibble pins them to your exact ZIP code.
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Sunflower in a Zone 9 season
Zone 9 gives about 275 frost-free days. Sunflower needs roughly 80 days from sowing. That leaves about 195 days of slack, so there is room for a late start or a second planting.
Sowing every 14 days, Zone 9 has room for about 14 plantings.
How to grow sunflowers
Sow sunflowers around your last frost date. Stagger plantings every couple of weeks for blooms all summer.
Companion plants
Good neighbors for Sunflower:
Better kept apart:
Sunflower in other zones
Not in Zone 9? Pick your zone for the same dated windows.
Keep exploring
Sunflower: the full growing guide · The Zone 9 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.