When to plant chinese cabbage (napa) in Sioux Falls, South Dakota

April 10 – April 17

Transplant outdoors · typical Sioux Falls year

Climate basis: NOAA station Sioux Falls, SD (USW00014944), 2 mi (3 km) from downtown Sioux Falls (ZCTA 57104 centroid), elevation 1430 ft, on the 1991–2020 climate normals. Transplant chinese cabbage (napa) outdoors from approximately the dates above, anchored to the median last spring 32°F freeze (May 1). One year in ten still freezes after May 14.

Last spring freezeMay 11-in-10 after May 14
First fall freezeOctober 61-in-10 before Sep 23
Frost-free season157 daysmedian at 32°F
Hard freeze, 28°Apr 22Oct 17kills even hardy greens
USDA zone5a-20 to -15°F winter low not frost timing

The Sioux Falls year

Start seeds indoorsMar 6 – Mar 20
Transplant outdoorsApr 10 – Apr 17
  • indoors under lights
  • in the garden
  • frost-free season
  • 1-in-10 years still freeze to May 14
Chinese Cabbage (Napa) in Sioux Falls · freeze context from Sioux Falls, SD, 1991–2020 normals.

Every method, with its sources

Start seeds indoors

Mar 6 – Mar 20

Arkansas Extension requires transplants no older than "four to five weeks" at setting out, so indoor sowing is counted back 28–35 days from the cited transplant window, giving last spring frost minus 56 to minus 42 days. Anchored to the median last spring freeze (May 1). University of Arkansas System Division of Agriculture, Cooperative Extension Service · Clemson Cooperative Extension, Home & Garden Information Center · Clemson Cooperative Extension, Home & Garden Information Center

Transplant outdoors

Apr 10 – Apr 17

Arkansas Extension states "Transplant two to three weeks before the last frost-free date", giving last spring frost minus 21 to minus 14 days; Clemson's warning that spring-frosted seedlings bolt is a caution on the same window, not a competing interval. Anchored to the median last spring freeze (May 1). Clemson Cooperative Extension, Home & Garden Information Center · Clemson Cooperative Extension, Home & Garden Information Center

Variety assumption: Offsets assume spring-set transplants of the 45–72 day Napa and Michihili types tabulated by Arkansas Extension; no fall window is encoded because every fall rule found for napa is fixed-calendar ("early to midsummer", "July") rather than frost-anchored.

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 (3)

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