When to plant zinnia 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

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Start indoors Mar 23 · Sow Apr 20 · First harvest Jun 9 · Wrap by Sep 1

Last spring frostApr 20

Start seeds indoorsMar 23

Direct sowApr 20

First harvestJun 9

Last harvestSep 1

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. Zinnia 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. Starting seeds indoors 4 weeks ahead gives strong transplants ready the moment the soil warms.

Common questions

How long does zinnia take to grow in zone 6b?

Zinnia matures in about 50–70 days from sowing. In zone 6b that means sowing around Apr 20 and first picking around Jun 9.

Will zinnia survive frost in zone 6b?

No — zinnia 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 zinnia growing guide →