When to plant basil in zone 10b — planting calendar

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Showing USDA Zone 10B

Growing SeasonZone 10b

Last frost ~Jan 15First frost ~Dec 31Today

Start indoorsTransplant / sowHarvestFrost risk

DECJANFEBMARAPRMAY

Start indoors Dec 18 · Sow Jan 29 · First harvest Feb 23 · Wrap by May 18

Last spring frostJan 15

Start seeds indoorsDec 18

Direct sowJan 29

First harvestFeb 23

Last harvestMay 18

First fall frostDec 31

Why these dates work in zone 10b

Zone 10b's last spring frost averages Jan 15 and first fall frost Dec 31 — about 350 frost-free days. Basil 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 basil take to grow in zone 10b?

Basil matures in about 25–35 days from sowing. In zone 10b that means sowing around Jan 29 and first picking around Feb 23.

Will basil survive frost in zone 10b?

No — basil is frost-sensitive. In zone 10b, wait until after the last frost (around Jan 15) to plant, and harvest before the first fall frost (around Dec 31).

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