When to plant radicchio in Fargo, North Dakota

May 10 – May 24

Transplant outdoors · typical Fargo year

Climate basis: NOAA station Fargo Hector INTL AP, ND (USW00014914), 1 mi (2 km) from downtown Fargo (ZCTA 58102 centroid), elevation 900 ft, on the 1991–2020 climate normals. Transplant radicchio outdoors from approximately the dates above, anchored to the median last spring 32°F freeze (May 10). One year in ten still freezes after May 23.

Last spring freezeMay 101-in-10 after May 23
First fall freezeSeptember 301-in-10 before Sep 18
Frost-free season143 daysmedian at 32°F
Hard freeze, 28°Apr 30Oct 10kills even hardy greens
USDA zone4a-30 to -25°F winter low not frost timing

The Fargo year

Transplant outdoorsMay 10 – May 24
Direct-sow outdoorsApr 12 – Apr 19
Fall plantingJul 2 – Jul 16
  • indoors under lights
  • in the garden
  • frost-free season
  • 1-in-10 years still freeze to May 23
Radicchio in Fargo · freeze context from Fargo Hector INTL AP, ND, 1991–2020 normals.

Every method, with its sources

Transplant outdoors

May 10 – May 24

USU places transplants near the last frost-free date, a point rule that is encoded as a 14-day planting span beginning at the last-freeze anchor. Anchored to the median last spring freeze (May 10). Utah State University Extension

Direct-sow outdoors

Apr 12 – Apr 19

USU states seeded radicchio may go in 3-4 weeks before the last frost-free date, and because the source gives an explicit range it is encoded directly as -28 to -21 days rather than expanded to a 14-day span. Anchored to the median last spring freeze (May 10). Utah State University Extension

Fall planting

Jul 2 – Jul 16

UMN sows the fall crop about three months before the average first fall frost, taken as a -90 day point and encoded as a 14-day span; USU's fall guidance is not combined here because it is anchored to an anticipated maturity date rather than stated directly against the frost date. Anchored to the median first fall freeze (Sep 30). University of Minnesota Extension

Start seeds indoors

Not calculated

No frost-anchored indoor-start window is published, because UMN gives indoor sowing as Minnesota calendar dates ('early April', and July for fall crops) rather than against a freeze date, and the alternative lead time it offers is measured from the transplant date rather than from an anchor, while USU states only that 5-6 weeks are generally required to grow transplants to set-out size.

Variety assumption: UMN gives radicchio about 60 to 70 days to mature, and USU advises selecting early-maturing cultivars for fall plantings.

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 (2)

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