PlantingWindowThe American Planting Almanac

When to plant mustard greens in Boston, Massachusetts

March 7 – March 21

Direct-sow outdoors · typical Boston year

Climate basis: NOAA station Boston Logan INTL AP, MA (USW00014739), 3 mi (5 km) from downtown Boston (ZCTA 02108 centroid), elevation 12 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 4). One year in ten still freezes after April 17.

Last spring freezeApril 41-in-10 after Apr 17
First fall freezeNovember 91-in-10 before Oct 29
Frost-free season≈ 218 daysmedian at 32°F
Hard freeze, 28°Mar 28 – Nov 21kills even hardy greens
USDA zone7a0 to 5°F winter low — not frost timing

The Boston year

Direct-sow outdoorsMar 7 – Mar 21
Fall plantingSep 14 – Oct 12
  • indoors under lights
  • in the garden
  • frost-free season
  • 1-in-10 years still freeze to Apr 17
Mustard greens in Boston · freeze context from Boston Logan INTL AP, MA, 1991–2020 normals.

Every method, with its sources

Direct-sow outdoors

Mar 7 – Mar 21

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 4). Purdue University Extension

Fall planting

Sep 14 – Oct 12

Purdue Table 2: plant fall mustard greens at least 4–8 weeks before the first fall frost. Anchored to the median first fall freeze (Nov 9). 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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