When to plant celeriac in Sioux Falls, South Dakota

May 1 – May 15

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 celeriac 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 indoorsFeb 20 – Mar 6
Transplant outdoorsMay 1 – May 15
  • indoors under lights
  • in the garden
  • frost-free season
  • 1-in-10 years still freeze to May 14
Celeriac in Sioux Falls · freeze context from Sioux Falls, SD, 1991–2020 normals.

Every method, with its sources

Start seeds indoors

Feb 20 – Mar 6

The UC Master Gardener Program of Sonoma County (University of California Cooperative Extension) says to "Sow seed indoors as early as 10 weeks before the average last frost date in spring," so the sowing span opens ten weeks before the last frost and runs two weeks; no competing extension figure was found, so this stands without reconciliation. Anchored to the median last spring freeze (May 1). University of California Cooperative Extension, UC Master Gardener Program of Sonoma County

Transplant outdoors

May 1 – May 15

The same UC Master Gardener page states plants "can go into the garden 10-12 in. apart on the average date of last frost," a point rule that opens a 14-day transplanting span at the last frost date; the page's alternative air- and soil-temperature condition is not frost-anchored and was therefore not encoded. Anchored to the median last spring freeze (May 1). University of California Cooperative Extension, UC Master Gardener Program of Sonoma County

Variety assumption: Assumes a standard 100-to-120-day celeriac variety grown from transplants; germination is slow, so the long indoor lead time is part of the published rule rather than an added buffer.

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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