Watermelon in Zone 10a & 10b
Citrullus lanatus
Yes, watermelon grows in zones 10a and 10b. Plant it outside in Feb–Jun.
When to plant watermelon 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–Jun |
| Estimated harvest | ~85 days after direct-sowing |
Spacing: about 10 square feet per plant (square-foot-gardening spacing). Mature height: 6-10 in.
Zone 10b dates sourced from growinginthegarden.com.
Plant alongside it in zone 10b
These go outside within two weeks of watermelon in zone 10b, so one planting day can cover them.
- TomatoFeb–Apr
- CucumberFeb–Apr
- ZucchiniFeb–Mar
- BroccoliniJan 30–Feb 6
- Napa Cabbage (Chinese Cabbage)Jan 30–Feb 6
- CantaloupeFeb–Jul
Watermelon asks for more room and more patience than almost anything else in a vegetable garden, at just 0.1 plants per square foot, a single vine can sprawl across a large share of a bed, and it takes most of a summer to deliver fruit.
How watermelon fits zone 10's season
Zone 10b's frost-free window runs about 324 days, from January 30 to December 20. Watermelon needs about 85 days from sowing to first harvest.
Watermelon 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 | Harvest |
|---|---|---|---|
| 5a & 5b | Not usually | May 24–May 31 | Aug 17–Aug 24 |
| 6a & 6b | Not usually | May 9–May 16 | Aug 2–Aug 9 |
| 7a & 7b | Not usually | Apr 24–May 1 | Jul 18–Jul 25 |
| 8a & 8b | Not usually | Apr 8–Apr 15 | Jul 2–Jul 9 |
| 9a & 9b | Not usually | Mar 1–Mar 8 | May 25–Jun 1 |
| 10a & 10bSpring window (your zone) | Not usually | Feb–Jun | ~85 days after direct-sowing |
| 11a & 11bFall window | Not usually | Dec–Mar | ~85 days after direct-sowing |
Harvest dates are about 85 days after the sow or plant-out date.
Good companions
- Sweet Corn: Corn provides light afternoon shade without heavy competition for space.
Where to buy watermelon seeds
Botanical Interests · True Leaf Market · Burpee · High Mowing Organic Seeds (each supplier's watermelon seeds)
Varieties we recommend, and where to get them:
- Crimson Sweet: Listed among Clemson Cooperative Extension's recommended standard seeded watermelon varieties for home gardens, a widely available, dependable classic large-fruited type. Buy: Botanical Interests · True Leaf Market · Burpee · High Mowing Organic Seeds Full notes
- Sangria: Also on Clemson's standard-seeded list, a large-fruited type alongside Crimson Sweet. Buy: True Leaf Market Full notes
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing watermelon" 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 Watermelon in USDA zone 10b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.
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