When to plant sunflower in zone 6b — planting calendar

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Showing USDA Zone 6B

Growing SeasonZone 6b

Last frost ~Apr 20First frost ~Oct 15Today

Start indoorsTransplant / sowHarvestFrost risk

APRMAYJUNJUL

Sow Apr 20 · First harvest Jun 19 · Wrap by Jul 17

Last spring frostApr 20

Direct sowApr 20

First harvestJun 19

Last harvestJul 17

First fall frostOct 15

Why these dates work in zone 6b

Zone 6b's last spring frost averages Apr 20 and first fall frost Oct 15 — about 178 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 6b?

Sunflower matures in about 60–100 days from sowing. In zone 6b that means sowing around Apr 20 and first picking around Jun 19.

Will sunflower survive frost in zone 6b?

No — sunflower is frost-sensitive. In zone 6b, wait until after the last frost (around Apr 20) to plant, and harvest before the first fall frost (around Oct 15).

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