When to plant sweet potato in zone 3b — planting calendar

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Showing USDA Zone 3B

Growing SeasonZone 3b

Last frost ~May 25First frost ~Sep 15Today

Start indoorsTransplant / sowHarvestFrost risk

JUNJULAUGSEP

Transplant Jun 15 · First harvest Sep 13 · Wrap by Sep 8

Last spring frostMay 25

Transplant outJun 15

First harvestSep 13

Last harvestSep 8

First fall frostSep 15

Why these dates work in zone 3b

Zone 3b's last spring frost averages May 25 and first fall frost Sep 15 — about 113 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 3b?

Sweet Potato matures in about 90–120 days from transplanting. In zone 3b that means setting plants out around Jun 15 and first picking around Sep 13.

Will sweet potato survive frost in zone 3b?

No — sweet potato is frost-sensitive. In zone 3b, wait until after the last frost (around May 25) to plant, and harvest before the first fall frost (around Sep 15).

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