PlantingWindowThe American Planting Almanac

When to plant mustard greens in Boise, Idaho

April 19 – May 3

Direct-sow outdoors · typical Boise year

Climate basis: NOAA station Boise 7 N, ID (USC00101017), 6 mi (9 km) from downtown Boise (ZCTA 83702 centroid), elevation 3885 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 (May 17). One year in ten still freezes after June 10.

Last spring freezeMay 171-in-10 after Jun 10
First fall freezeOctober 121-in-10 before Sep 27
Frost-free season≈ 147 daysmedian at 32°F
Hard freeze, 28°Apr 27 – Oct 24kills even hardy greens
USDA zone7a0 to 5°F winter low — not frost timing

The Boise year

Direct-sow outdoorsApr 19 – May 3
Fall plantingAug 17 – Sep 14
  • indoors under lights
  • in the garden
  • frost-free season
  • 1-in-10 years still freeze to Jun 10
Mustard greens in Boise · freeze context from Boise 7 N, ID, 1991–2020 normals.

Every method, with its sources

Direct-sow outdoors

Apr 19 – May 3

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 (May 17). Purdue University Extension

Fall planting

Aug 17 – Sep 14

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 12). 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)

Keep exploring

This crop, other cities
Related crops in Boise
Local overview