Washington planting calendar

When to plant cauliflower in Washington — sow, transplant & harvest dates

Washington is mostly USDA zone 8a (range 4a-9a). Dates below are derived from cauliflower's frost tolerance and Washington's frost window — not generic national averages.

Cauliflower planting timetable for Washington

Stage	When in Washington	Anchor
Start seeds indoors	early March (March 4)	6 weeks before the last frost (mid-April (Puget Sound))
Transplant outside	early April (April 1)	14 days before the last frost (mid-April (Puget Sound))
First harvest (estimate)	late June (June 25)	~85 days from transplant

Dates are state-wide averages for the dominant zone. Local microclimates — elevation, urban heat, coastal moderation — can shift the window by 1-2 weeks. Use the frost-date calculator for a date tuned to your town.

Why Washington's climate shifts the cauliflower dates

Washington's last spring frost averages mid-April (Puget Sound) and first fall frost early November (Puget Sound), which sets the whole planting clock. Washington is split by the Cascades into a mild, wet, long-season west and a colder, drier east. The Puget Sound lowland is the mildest belt. Sow early — cauliflower bolt once daytime temperatures hold above 24 °C, so the earlier they go in, the longer the harvest.

More temperature-sensitive than broccoli — optimal growing range is 15–18 °C (60–65 °F); temperatures above 27 °C (80 °F) cause loose, ricey curds, while a sharp frost below −3 °C (27 °F) can damage developing heads. Start indoors 6–8 weeks before last frost and transplant 2–3 weeks before last frost. Blanch white varieties by tying outer leaves over the curd when it reaches golf-ball size, or choose self-blanching types. Succession planting is difficult in spring in hot climates (zones 7+); fall crops from a midsummer sowing are often more reliable.

Frost-risk note

Don't plant before mid-April (Puget Sound) — a hard freeze can still set young plants back. In the Cascades and northeast highlands (zone 4a) the safe date runs a week or two later.

Regional variation within Washington

the Cascades and northeast highlands (zone 4a) runs roughly 1-2 weeks behind the state average; the Puget Sound lowland around Seattle (zone 9a) can plant 1-2 weeks earlier.

Seattle — USDA zone 9a
Spokane — USDA zone 7a
Tacoma — USDA zone 8b
Vancouver — USDA zone 8b
Yakima — USDA zone 7a

What else to plant in Washington around then

The same early window suits peas, lettuce, spinach, and onion sets.

Quick-grow guide

Sun: Full sun — 6+ hours direct.
Soil temperature for germination: 7–24 °C (45–75 °F).
Spacing: 18–24 inches (45–60 cm) between plants.
Days to harvest: ~85 days from planting out.

Frequently asked questions

When is the best time to plant cauliflower in Washington?

In Washington (mostly USDA zone 8a), sow cauliflower indoors around early March, transplant outdoors early April (before the last frost, mid-April), and harvest from late June. Cauliflower are half-hardy — young plants shrug off a light frost but not a hard freeze, so sowing can start a couple of weeks before the last spring frost.

What USDA zone is Washington?

Most of Washington sits in USDA hardiness zone 8a, with the state spanning roughly 4a-9a from the Cascades and northeast highlands (zone 4a) to the Puget Sound lowland around Seattle (zone 9a). The last spring frost averages mid-April (Puget Sound) and the first fall frost early November (Puget Sound).

Can you grow cauliflower in Washington?

Yes. Washington's dominant zone 8a supports cauliflower — the key is timing. Cauliflower are half-hardy — young plants shrug off a light frost but not a hard freeze, so sowing can start a couple of weeks before the last spring frost.

Does the planting date change across Washington?

the Cascades and northeast highlands (zone 4a) runs roughly 1-2 weeks behind the state average; the Puget Sound lowland around Seattle (zone 9a) can plant 1-2 weeks earlier.

What else can I plant in Washington around the same time?

The same early window suits peas, lettuce, spinach, and onion sets.

Source and methodology

State zone spans from the USDA Plant Hardiness Zone Map (2023); frost-date averages from NOAA Climate Data Online. Hot-state two-season timing cross-checked against the UF/IFAS Florida Gardening Calendar and the University of Arizona Cooperative Extension planting calendar. Curated by the Growli editorial team.