Sunflower in Zone 10a & 10b
Helianthus annuus
Yes, sunflower grows in zones 10a and 10b. Plant it outside in Feb–Aug.
When to plant sunflower in zone 10b
Zones 10a and 10b share the same average frost dates, so this page covers both.
Method: Direct sow: Direct-sow outside. It 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 | ~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.
Plant alongside it in zone 10b
These go outside within two weeks of sunflower in zone 10b, so one planting day can cover them.
- MarigoldFeb–May
- DahliaFeb–Apr
- African DaisyJan 30–Feb 6
- Amaranthus (Love-Lies-Bleeding)Jan 30–Feb 6
- Ammi (False Queen Anne's Lace)Jan 30–Feb 6
- Ammobium (Winged Everlasting)Jan 30–Feb 6
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 bloom.
Sunflower planting windows in every zone
Zone 10b is highlighted. Useful for comparing against a neighbouring zone, or for a garden somewhere else.
| Zone | Start indoors | Sow or plant out | Bloom |
|---|---|---|---|
| 2a & 2b | Not usually | May 20–May 27 | Aug 8–Aug 15 |
| 3a & 3b | Not usually | May 30–Jun 6 | Aug 18–Aug 25 |
| 4a & 4b | Not usually | May 15–May 22 | Aug 3–Aug 10 |
| 5a & 5b | Not usually | May 10–May 17 | Jul 29–Aug 5 |
| 6a & 6b | Not usually | Apr 25–May 2 | Jul 14–Jul 21 |
| 7a & 7b | Not usually | Apr 10–Apr 17 | Jun 29–Jul 6 |
| 8a & 8b | Not usually | Mar 25–Apr 1 | Jun 13–Jun 20 |
| 9a & 9b | Not usually | Feb 15–Feb 22 | May 6–May 13 |
| 10a & 10bSpring window (your zone) | Not usually | Feb–Aug | ~80 days after direct-sowing |
| 11a & 11b | Not usually | Jan 1–Jan 8 | Mar 22–Mar 29 |
Bloom dates are about 80 days after the sow or plant-out date.
Zone 2 sows before zone 3 here, which looks wrong and is not. USDA zones rank winter cold, not season length, and zone 2 is mostly interior Alaska, where hard winters come with warm summers. More on what a zone measures.
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
Botanical Interests · True Leaf Market · Burpee · High Mowing Organic Seeds (each supplier's sunflower seeds)
Varieties we recommend, and where to get them:
- 'Autumn Beauty' (branching): Virginia Cooperative Extension lists this as a branching type, producing multiple blooms per plant over a long period rather than Mammoth Russian's single head. Buy: True Leaf Market · Burpee · High Mowing Organic Seeds Full notes
- 'Teddy Bear' (dwarf): Listed by Virginia Cooperative Extension as a dwarf type, under 3 feet, producing one oversized head on a short stem. Buy: Botanical Interests · True Leaf Market · Burpee · High Mowing Organic Seeds Full notes
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 · 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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