PlantingWindowThe American Planting Almanac

When to plant kale in Detroit, Michigan

March 31 – April 14

Direct-sow outdoors · typical Detroit year

Climate basis: NOAA station Detroit City AP, MI (USW00014822), 6 mi (9 km) from downtown Detroit (ZCTA 48226 centroid), elevation 626 ft, on the 1991–2020 climate normals. Direct-sow kale from approximately the dates above, anchored to the median last spring 32°F freeze (April 21). One year in ten still freezes after May 6.

Last spring freezeApril 211-in-10 after May 6
First fall freezeOctober 311-in-10 before Oct 17
Frost-free season≈ 190 daysmedian at 32°F
Hard freeze, 28°Apr 8 – Nov 9kills even hardy greens
USDA zone6b-5 to 0°F winter low — not frost timing

The Detroit year

Direct-sow outdoorsMar 31 – Apr 14
Fall plantingSep 5 – Oct 3
  • indoors under lights
  • in the garden
  • frost-free season
  • 1-in-10 years still freeze to May 6
Kale in Detroit · freeze context from Detroit City AP, MI, 1991–2020 normals.

Every method, with its sources

Direct-sow outdoors

Mar 31 – Apr 14

Purdue: hardy — 4–6 weeks before the last frost; Penn State's earliest sowing Apr 10 (−21 days) is the later start and is used. Anchored to the median last spring freeze (Apr 21). Penn State Extension (York County Master Gardeners) · Purdue University Extension

Fall planting

Sep 5 – Oct 3

Purdue Table 2: plant fall kale at least 4–8 weeks before the first fall frost. Anchored to the median first fall freeze (Oct 31). Purdue University Extension

Variety assumption: Assumes an average curly variety (about 50–65 days; Penn State lists 60).

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)

Keep exploring

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