When to plant zinnia in zone 5a — planting calendar

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Showing USDA Zone 5A

Growing SeasonZone 5a

Last frost ~May 10First frost ~Oct 1Today

Start indoorsTransplant / sowHarvestFrost risk

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Start indoors Apr 12 · Sow May 10 · First harvest Jun 29 · Wrap by Sep 21

Last spring frostMay 10

Start seeds indoorsApr 12

Direct sowMay 10

First harvestJun 29

Last harvestSep 21

First fall frostOct 1

Why these dates work in zone 5a

Zone 5a's last spring frost averages May 10 and first fall frost Oct 1 — about 144 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 5a?

Zinnia matures in about 50–70 days from sowing. In zone 5a that means sowing around May 10 and first picking around Jun 29.

Will zinnia survive frost in zone 5a?

No — zinnia is frost-sensitive. In zone 5a, wait until after the last frost (around May 10) to plant, and harvest before the first fall frost (around Oct 1).

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