When to plant sweet potatoes in Anchorage, Alaska

May 15 – May 29

Transplant outdoors · typical Anchorage year

Climate basis: NOAA station Anchorage Merrill Fld, AK (USW00026409), 0 mi (0 km) from downtown Anchorage (ZCTA 99501 centroid), elevation 138 ft, on the 1991–2020 climate normals. Plant sweet potato slips from approximately the dates above, anchored to the median last spring 32°F freeze (May 1). One year in ten still freezes after May 9.

Last spring freezeMay 11-in-10 after May 9
First fall freezeSeptember 291-in-10 before Sep 17
Frost-free season150 daysmedian at 32°F
Hard freeze, 28°Apr 19Oct 8kills even hardy greens
USDA zone5a-20 to -15°F winter low not frost timing

The Anchorage year

Transplant outdoorsMay 15 – May 29
  • indoors under lights
  • in the garden
  • frost-free season
  • 1-in-10 years still freeze to May 9
Sweet potatoes in Anchorage · freeze context from Anchorage Merrill Fld, AK, 1991–2020 normals.

Every method, with its sources

Transplant outdoors

May 15 – May 29

Purdue: very tender (vegetatively propagated) — plant slips at least two weeks after the average last frost. Anchored to the median last spring freeze (May 1). Purdue University Extension

Start seeds indoors

Not calculated

The cited extension guides do not time an indoor seed-starting window for this crop.

Direct-sow outdoors

Not calculated

Sweet potatoes are grown from slips, not seed.

Fall planting

Not calculated

No source-backed fall planting rule exists for this crop in the registry, so no fall window is calculated.

Variety assumption: Assumes an average variety (about 100–120 days of warm weather from slips).

These windows describe typical years (1991–2020 climate normals), not this year's forecast. Freezes happen outside them — especially in frost pockets, valleys, and urban edges. Watch the forecast before committing tender plants.

This week, not a typical year:
Crop rule sources (1)

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