When to plant marigold in zone 4a — planting calendar

Not your zone?

Showing USDA Zone 4A

Growing SeasonZone 4a

Last frost ~May 20First frost ~Sep 20Today

Start indoorsTransplant / sowHarvestFrost risk

MARAPRMAYJUNJULAUGSEP

Start indoors Apr 8 · Sow May 20 · First harvest Jul 4 · Wrap by Sep 13

Last spring frostMay 20

Start seeds indoorsApr 8

Direct sowMay 20

First harvestJul 4

Last harvestSep 13

First fall frostSep 20

Why these dates work in zone 4a

Zone 4a's last spring frost averages May 20 and first fall frost Sep 20 — about 123 frost-free days. Marigold 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 6 weeks ahead gives strong transplants ready the moment the soil warms.

Common questions

How long does marigold take to grow in zone 4a?

Marigold matures in about 45–55 days from sowing. In zone 4a that means sowing around May 20 and first picking around Jul 4.

Will marigold survive frost in zone 4a?

No — marigold is frost-sensitive. In zone 4a, wait until after the last frost (around May 20) to plant, and harvest before the first fall frost (around Sep 20).

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