Watermelon in Zone 10a & 10b
Citrullus lanatus
When to plant watermelon 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. Watermelon 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 | Apr 27–Sep 23 (~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.
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.
Good companions
- Sweet Corn: Corn provides light afternoon shade without heavy competition for space.
Where to buy watermelon seeds
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 · Full companion planting guide · Full plant profile · 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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