When to plant basil 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 · Sow Mar 1 · First harvest Mar 26 · Wrap by Jun 18

Last spring frostFeb 15

Start seeds indoorsJan 18

Direct sowMar 1

First harvestMar 26

Last harvestJun 18

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. 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 9b?

Basil matures in about 25–35 days from sowing. In zone 9b that means sowing around Mar 1 and first picking around Mar 26.

Will basil survive frost in zone 9b?

No — basil 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 basil growing guide →