Sunflower in Zone 10a & 10b
Helianthus annuus
When to plant sunflower in zone 10b
Zones 10a and 10b share the same average frost dates in our data, so this page covers both.
Method: Direct sow: Direct-sow outside. Sunflower doesn't transplant well, or doesn't need the extra time indoors.
| Window | Spring window |
|---|---|
| Start indoors | Not typically started indoors |
| Direct sow / transplant outside | Feb–Aug |
| Estimated bloom | Apr 22–Nov 19 (~80 days after direct-sowing) |
Spacing: about 2 square feet per plant (square-foot-gardening spacing). Mature height: 3-12 ft.
Zone 10b dates sourced from growinginthegarden.com.
Sunflowers are one of the few flowers in a vegetable garden that does actual structural work: a single or branching stalk anywhere from 3 to 12-plus feet tall, topped with big daisy-form heads (yellow petals ringing a dark brown center, though some varieties run red or bronze), can serve as a living trellis for pole beans or climbing cucumbers, instead of building one out of stakes and twine.
How sunflower fits zone 10's season
Zone 10b's frost-free window runs about 324 days, from January 30 to December 20. Sunflower needs about 80 days from sowing to first harvest.
Good companions
- Bush Beans: Sturdy stalk can serve as a living trellis for pole beans once well established.
- Cucumber: Sturdy stalk can serve as a living trellis for climbing cucumbers.
Where to buy sunflower seeds
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing sunflower" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 10b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →
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Growing Sunflower in USDA zone 10b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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