When to plant watermelon in zone 9b — planting calendar

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Showing USDA Zone 9B

Growing SeasonZone 9b

Last frost ~Feb 15First frost ~Dec 10Today

Start indoorsTransplant / sowHarvestFrost risk

JANFEBMARAPRMAYJUN

Start indoors Jan 18 · Transplant Mar 1 · First harvest May 10 · Wrap by May 31

Last spring frostFeb 15

Start seeds indoorsJan 18

Transplant outMar 1

First harvestMay 10

Last harvestMay 31

First fall frostDec 10

Why these dates work in zone 9b

Zone 9b's last spring frost averages Feb 15 and first fall frost Dec 10 — about 298 frost-free days. Watermelon is frost-sensitive, so the 2w after frost timing builds in a safety margin against a late cold snap — setting plants out too early risks losing them to frost. Starting seeds indoors 4 weeks ahead gives strong transplants ready the moment the soil warms.

Common questions

How long does watermelon take to grow in zone 9b?

Watermelon matures in about 70–90 days from transplanting. In zone 9b that means setting plants out around Mar 1 and first picking around May 10.

Will watermelon survive frost in zone 9b?

No — watermelon is frost-sensitive. In zone 9b, wait until after the last frost (around Feb 15) to plant, and harvest before the first fall frost (around Dec 10).

For soil, spacing, pests and companion planting, see the full watermelon growing guide →