When to plant radicchio in Des Moines, Iowa

April 18 – May 2

Transplant outdoors · typical Des Moines year

Climate basis: NOAA station Des Moines INTL AP, IA (USW00014933), 4 mi (6 km) from downtown Des Moines (ZCTA 50309 centroid), elevation 957 ft, on the 1991–2020 climate normals. Transplant radicchio outdoors from approximately the dates above, anchored to the median last spring 32°F freeze (April 18). One year in ten still freezes after May 2.

Last spring freezeApril 181-in-10 after May 2
First fall freezeOctober 201-in-10 before Oct 4
Frost-free season184 daysmedian at 32°F
Hard freeze, 28°Apr 8Oct 30kills even hardy greens
USDA zone5b-15 to -10°F winter low not frost timing

The Des Moines year

Transplant outdoorsApr 18 – May 2
Direct-sow outdoorsMar 21 – Mar 28
Fall plantingJul 22 – Aug 5
  • indoors under lights
  • in the garden
  • frost-free season
  • 1-in-10 years still freeze to May 2
Radicchio in Des Moines · freeze context from Des Moines INTL AP, IA, 1991–2020 normals.

Every method, with its sources

Transplant outdoors

Apr 18 – May 2

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 (Apr 18). Utah State University Extension

Direct-sow outdoors

Mar 21 – Mar 28

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 (Apr 18). Utah State University Extension

Fall planting

Jul 22 – Aug 5

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 (Oct 20). 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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