When to plant rutabaga in Seattle, Washington
August 9 – August 23
Fall planting · typical Seattle yearClimate 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. Plant rutabaga for fall from approximately the dates above, anchored to the median first fall 32°F freeze (November 17). One year in ten still freezes after April 1.
The Seattle year
- indoors under lights
- in the garden
- frost-free season
- 1-in-10 years still freeze to Apr 1
Every method, with its sources
Fall planting
Aug 9 – Aug 23University of Illinois Extension says "For fall harvest, plant rutabagas about 100 days before the first frost," a point rule that opens a 14-day sowing span 100 days ahead of the first fall freeze; UGA Circular 942 agrees the crop is frost-anchored ("2 ½ to three months before a heavy frost") but ties itself to a heavy frost rather than the first 32°F freeze that this engine uses as its anchor, so the Illinois wording — which names the first frost directly — was the one encoded. Anchored to the median first fall freeze (Nov 17). University of Illinois Extension · University of Georgia Extension
Start seeds indoors
Not calculatedThe cited extension guides do not time an indoor seed-starting window for this crop.
Transplant outdoors
Not calculatedThe cited extension guides do not time an outdoor transplanting window for this crop.
Direct-sow outdoors
Not calculatedIllinois Extension states a frost-relative rule only for the fall crop ("plant rutabagas about 100 days before the first frost"); its spring sentence covers turnips rather than rutabagas, so no spring window is computed here.
Variety assumption: Assumes a standard 90-day variety such as American Purple Top or Laurentian grown as a fall crop; Illinois Extension notes rutabagas need about four weeks longer than turnips, which is why only a fall window is encoded.
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.
Crop rule sources (2)
- University of Illinois Extension: Turnip | Home Vegetable Gardening (accessed 2026-07-25)"For fall harvest, plant rutabagas about 100 days before the first frost, and plant turnips about 3 to 4 weeks later."
- University of Georgia Extension: Growing Rutabagas in the Home Garden (Circular 942), Terry Kelley and Robert Westerfield (accessed 2026-07-25)"Rutabagas should be seeded 2 ½ to three months before a heavy frost."