When to plant corn 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

FEBMARAPRMAYJUN

Sow Mar 1 · First harvest May 10 · Wrap by May 31

Last spring frostFeb 15

Direct sowMar 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. Corn 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.

Common questions

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

Corn matures in about 70–90 days from sowing. In zone 9b that means sowing around Mar 1 and first picking around May 10.

Will corn survive frost in zone 9b?

No — corn 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 corn growing guide →