When to plant parsley in Seattle, Washington

February 20 – March 6

Transplant 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. Transplant parsley outdoors 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

Start seeds indoorsDec 12 – Dec 26

Transplant outdoorsFeb 20 – Mar 6

Direct-sow outdoorsFeb 13 – Feb 27

indoors under lights
in the garden
frost-free season
1-in-10 years still freeze to Apr 1

Parsley in Seattle · freeze context from Seattle Boeing Fld, WA, 1991–2020 normals.

Every method, with its sources

Start seeds indoors

Dec 12 – Dec 26

Wisconsin: start seeds indoors 8–10 weeks before the last frost (UNH: 9–10 weeks from seed to transplant). Parsley germinates slowly. Anchored to the median last spring freeze (Mar 13). University of Wisconsin–Madison Division of Extension (Wisconsin Horticulture) · University of New Hampshire Extension

Transplant outdoors

Feb 20 – Mar 6

UNH: set out 2–3 weeks before the last frost; Oklahoma State plants 3–4 weeks before. The later UNH range is used. Anchored to the median last spring freeze (Mar 13). University of New Hampshire Extension · Oklahoma State University Extension

Direct-sow outdoors

Feb 13 – Feb 27

Oklahoma State Table 1: plant parsley three to four weeks before the last spring frost. Anchored to the median last spring freeze (Mar 13). Oklahoma State University Extension

Variety assumption: Leaf harvest begins about 70–90 days from seed.

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 (3)

University of Wisconsin–Madison Division of Extension (Wisconsin Horticulture): Parsley, Petroselinum crispum (accessed 2026-07-24)
"Start seeds indoors 8-10 weeks before last frost."
University of New Hampshire Extension: Growing Vegetables: When to Plant Your Vegetable Garden [fact sheet] (accessed 2026-07-24)
Per-crop 'time from seed to transplant' and 'safe to set out in garden' relative to last frost.
Oklahoma State University Extension: Culinary Herbs for Oklahoma Gardens: Culture, Use and Preservation (accessed 2026-07-24)
Table 1 planting times relative to last spring frost for common herbs.

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