PlantingWindowThe American Planting Almanac

When to plant mustard greens in Philadelphia, Pennsylvania

March 2 – March 16

Direct-sow outdoors · typical Philadelphia year

Climate basis: NOAA station Phila Franklin Inst, PA (USC00366886), 1 mi (1 km) from downtown Philadelphia (ZCTA 19107 centroid), elevation 60 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 (March 30). One year in ten still freezes after April 12.

Last spring freezeMarch 301-in-10 after Apr 12
First fall freezeNovember 171-in-10 before Nov 4
Frost-free season≈ 232 daysmedian at 32°F
Hard freeze, 28°Mar 17 – Nov 29kills even hardy greens
USDA zone7b5 to 10°F winter low — not frost timing

The Philadelphia year

Direct-sow outdoorsMar 2 – Mar 16
Fall plantingSep 22 – Oct 20
  • indoors under lights
  • in the garden
  • frost-free season
  • 1-in-10 years still freeze to Apr 12
Mustard greens in Philadelphia · freeze context from Phila Franklin Inst, PA, 1991–2020 normals.

Every method, with its sources

Direct-sow outdoors

Mar 2 – Mar 16

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 (Mar 30). Purdue University Extension

Fall planting

Sep 22 – Oct 20

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 17). 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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