When to plant sunflower 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

FEBMARAPRMAY

Sow Feb 15 · First harvest Apr 16 · Wrap by May 14

Last spring frostFeb 15

Direct sowFeb 15

First harvestApr 16

Last harvestMay 14

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. Sunflower is frost-sensitive, so the around last 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 sunflower take to grow in zone 9b?

Sunflower matures in about 60–100 days from sowing. In zone 9b that means sowing around Feb 15 and first picking around Apr 16.

Will sunflower survive frost in zone 9b?

No — sunflower 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 sunflower growing guide →