PlantingWindowThe American Planting Almanac

When to plant collards in Seattle, Washington

February 27 – March 13

Direct-sow outdoors · typical Seattle year

Climate basis: NOAA station Seattle Boeing Fld, WA (USW00024234), 5 mi (8 km) from downtown Seattle (ZCTA 98104 centroid), elevation 20 ft, on the 1991–2020 climate normals. Direct-sow collards from approximately the dates above, anchored to the median last spring 32°F freeze (March 13). One year in ten still freezes after April 1.

Last spring freezeMarch 131-in-10 after Apr 1
First fall freezeNovember 171-in-10 before Nov 1
Frost-free season≈ 247 daysmedian at 32°F
Hard freeze, 28°Feb 18 – Dec 2kills even hardy greens
USDA zone9a20 to 25°F winter low — not frost timing

The Seattle year

Direct-sow outdoorsFeb 27 – Mar 13
Fall plantingSep 22 – Oct 20
  • indoors under lights
  • in the garden
  • frost-free season
  • 1-in-10 years still freeze to Apr 1
Collards in Seattle · freeze context from Seattle Boeing Fld, WA, 1991–2020 normals.

Every method, with its sources

Direct-sow outdoors

Feb 27 – Mar 13

Purdue: hardy — 4–6 weeks before the last frost; Penn State's earliest sowing Apr 17 (−14 days) is the later start and is used. Anchored to the median last spring freeze (Mar 13). Penn State Extension (York County Master Gardeners) · Purdue University Extension

Fall planting

Sep 22 – Oct 20

Purdue Table 2: plant fall collards at least 4–8 weeks before the first fall frost. Anchored to the median first fall freeze (Nov 17). Purdue University Extension

Variety assumption: Assumes an average variety (about 70–80 days; Penn State lists 80).

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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