Plant Sunflowers in Zone 13b
Seed-starting, transplant & harvest dates for USDA Zone 13b
Zone 13b is effectively frost-free, so the Zone 13b calendar for sunflowers is set by heat, not cold. There is no last frost to count backward from and no first frost to beat, which means the question is not whether sunflowers will finish but whether it will sit through the hottest stretch of the year. Sunflowers is a half-hardy crop needing about 80 days from sowing to harvest.
Fall planting: sunflowers in Zone 13b
Sunflowers has no useful fall window in Zone 13b. Sunflowers need a long run of warm, long days and will not finish from a late-summer sowing outside frost-free zones.
Sunflowers need a long run of warm, long days and will not finish from a late-summer sowing outside frost-free zones.
Fall dates are counted backward from the Zone 13b average first frost, not forward from a sowing date. See the fall planting calendar by zone for the full method.
Spring vs fall sunflowers in Zone 13b
| Planting | Sow or start | In the ground | Harvest |
|---|---|---|---|
| Spring | Feb 1 | Feb 1 | Apr 22 |
| Fall | — | — | — |
Sunflowers in nearby zones
Further reading on sunflowers
- Last frost date and what to plant before it
Why sunflowers can go out before your last frost, and how far before.
- Companion planting chart
What to plant with sunflowers and what to keep away from it.
Other crops in Zone 13b
Frequently asked questions
When should I start sunflowers in Zone 13b?
Direct sow outdoors around Feb 1.
Can I direct sow sunflowers in Zone 13b?
Yes, direct sow around Feb 1.
Can I plant sunflowers in the fall in Zone 13b?
Sunflowers has no useful fall window in Zone 13b. Sunflowers need a long run of warm, long days and will not finish from a late-summer sowing outside frost-free zones.
Will sunflowers survive frost in Zone 13b?
No. Sunflowers is a half-hardy crop and a single light frost ends it, so every Zone 13b planting has to finish before the average first frost (Zone 13b rarely sees one).