When to plant cauliflower in Washington
Washington’s average last spring frost is April 20, and the first fall frost typically arrives around October 15 — about 178 frost-free days (USDA zones 4b, 5b, 6b, 7b, 8a, 8b, 9a). Cauliflower needs 60–90 days to mature, which fits comfortably within Washington's growing season.
Washington covers a wide range of climates, so your exact frost dates may differ from the state average by two weeks or more. For dates tuned to your town, use the calendar generator.
When to plant cauliflower in Washington: the short answer
For a spring planting, plant out Mar 30 – Apr 16, with seeds started indoors Mar 2 – Mar 16. Seeds germinate in soil from 45 to 85°F.
Windows are ~1–2 week bands around each date. Frost dates are a statewide average from NOAA/NCEI normals; your town may differ by two weeks or more. Calendar year 2026.
How to grow cauliflower in Washington, step by step
- Start seeds indoors (Mar 2 – Mar 16). Sow seeds ½ inch deep in seed-starting mix under bright light. They take 5-10 days to sprout, fastest in soil around 75°F. Harden seedlings off for a week before they go outside.
- Prepare the bed. It needs at least six to eight hours of direct sun a day and loose soil at least 18 inches deep, with a pH between 6.0 and 7.5. Dig in compost before planting.
- Plant out (Mar 30 – Apr 16). Space plants about 18 inches apart in rows 30 inches apart. It tolerates a light frost but not a hard freeze. As a cool-season crop it does best before summer heat arrives in Washington.
- Water and feed. It needs plenty of water; keep the soil evenly moist and never let it dry out.
- Watch for pests and problems. Pests: cabbage worm, cabbage looper, aphids, cabbage root maggot. Diseases and disorders: clubroot, black rot, downy mildew.
- Harvest (from about Jun 5 – Jul 5). Cauliflower takes 60-90 days to reach harvest. The fussiest brassica - any check from cold, heat, or drought ruins the head. Fall crops are far more reliable than spring. Blanch white types by tying leaves over the curd.
Figures come from our crop data; dates use Washington’s average frost dates. More in the full cauliflower growing guide.
Cauliflower planting dates by USDA zone in Washington
Washington spans USDA zones 4b, 5b, 6b, 7b, 8a, 8b, 9a. Colder zones, usually higher or further inland, have a later last spring frost and an earlier first fall frost than the state average, so the cauliflower dates shift with them.
| Zone | Last frost | First frost | Season | Start indoors | Plant cauliflower |
|---|---|---|---|---|---|
| Zone 4 | May 10 | Sep 25 | 135 days | Mar 22 – Apr 5 | Apr 19 – May 6 |
| Zone 5 | Apr 30 | Oct 5 | 160 days | Mar 12 – Mar 26 | Apr 9 – Apr 26 |
| Zone 6 | Apr 15 | Oct 15 | 185 days | Feb 25 – Mar 11 | Mar 25 – Apr 11 |
| Zone 7 | Apr 5 | Oct 25 | 200 days | Feb 15 – Mar 1 | Mar 15 – Apr 1 |
| Zone 8 | Mar 20 | Nov 5 | 230 days | Jan 30 – Feb 13 | Feb 27 – Mar 16 |
| Zone 9 | Feb 20 | Nov 30 | 280 days | Jan 2 – Jan 16 | Jan 30 – Feb 16 |
When to plant cauliflower in nearby states
| State | Last frost | Plant out |
|---|---|---|
| Washington (this page) | April 20 | Mar 30 – Apr 16 |
| Oregon | April 20 | Mar 30 – Apr 16 |
Questions gardeners in Washington ask
When is the best time to plant cauliflower in Washington?
Plant cauliflower transplants outdoors in Washington between March 30 and April 16. That timing is set by Washington's average last spring frost of April 20; Washington spans several climates, so cooler and higher parts of the state run later.
When should I start cauliflower seeds indoors in Washington?
Start seeds indoors between March 2 and March 16, about 6 weeks before the last frost, so the seedlings are ready to plant out from March 30.
Can I plant cauliflower in the fall in Washington?
Yes. For a fall crop, start transplants between July 6 and July 23, so the crop matures in cool weather before Washington's first frost around October 15.
When will cauliflower planted in Washington be ready to harvest?
Planted on time, cauliflower is usually ready from about June 5 to July 5, 60-90 days after transplanting.
When is the last frost in Washington?
On average around April 20, with the first fall frost around October 15 - about 178 frost-free days. Your town may differ by two weeks or more.