When to plant sweet potato in zone 4a — planting calendar

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Showing USDA Zone 4A

Growing SeasonZone 4a

Last frost ~May 20First frost ~Sep 20Today

Start indoorsTransplant / sowHarvestFrost risk

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Transplant Jun 10 · First harvest Sep 8 · Wrap by Sep 13

Last spring frostMay 20

Transplant outJun 10

First harvestSep 8

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. Sweet Potato is frost-sensitive, so the 3w after 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 sweet potato take to grow in zone 4a?

Sweet Potato matures in about 90–120 days from transplanting. In zone 4a that means setting plants out around Jun 10 and first picking around Sep 8.

Will sweet potato survive frost in zone 4a?

No — sweet potato 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 sweet potato growing guide →