PlantingWindowThe American Planting Almanac

When to plant mustard greens in Milwaukee, Wisconsin

March 29 – April 12

Direct-sow outdoors · typical Milwaukee year

Climate basis: NOAA station West Allis, WI (USC00479046), 6 mi (10 km) from downtown Milwaukee (ZCTA 53202 centroid), elevation 723 ft, on the 1991–2020 climate normals. Direct-sow mustard greens from approximately the dates above, anchored to the median last spring 32°F freeze (April 26). One year in ten still freezes after May 12.

Last spring freezeApril 261-in-10 after May 12
First fall freezeOctober 221-in-10 before Oct 7
Frost-free season≈ 177 daysmedian at 32°F
Hard freeze, 28°Apr 14 – Nov 1kills even hardy greens
USDA zone6a-10 to -5°F winter low — not frost timing

The Milwaukee year

Direct-sow outdoorsMar 29 – Apr 12
Fall plantingAug 27 – Sep 24
  • indoors under lights
  • in the garden
  • frost-free season
  • 1-in-10 years still freeze to May 12
Mustard greens in Milwaukee · freeze context from West Allis, WI, 1991–2020 normals.

Every method, with its sources

Direct-sow outdoors

Mar 29 – Apr 12

Purdue lists mustard under both hardy (4–6 weeks before the last frost) and semi-hardy (2–4 weeks before); the later semi-hardy start is used. Anchored to the median last spring freeze (Apr 26). Purdue University Extension

Fall planting

Aug 27 – Sep 24

Purdue Table 2: plant fall mustard greens at least 4–8 weeks before the first fall frost. Anchored to the median first fall freeze (Oct 22). Purdue University Extension

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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