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 once the soil has warmed and the weather is settled. Stagger plantings every couple of weeks for a long run of blooms. Tall types may need a stake in windy spots.
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.