State growing guide
Washington Planting Guide
USDA Zone 8a/8b · Last frost Mar 20 · First frost Nov 5 · 229 days
Zone-specific planting calendar, major city frost dates, top crops, and Duke's tips for growing food in Washington.
Frost Dates by City — Washington
Average frost dates for major Washington cities. Use these to calculate your indoor start dates and transplant windows.
| City | USDA Zone | Last Spring Frost | First Fall Frost | Tomato Transplant Window |
|---|---|---|---|---|
| Seattle | 8b | Mar 10 | Nov 15 | ~2 wks after (Mar 10) |
| Tacoma | 8a | Mar 20 | Nov 5 | ~2 wks after (Mar 20) |
| Spokane | 6a | Apr 20 | Oct 15 | ~2 wks after (Apr 20) |
| Yakima | 6a | Apr 20 | Oct 15 | ~2 wks after (Apr 20) |
| Olympia | 8a | Mar 20 | Nov 1 | ~2 wks after (Mar 20) |
| Bellingham | 8a | Mar 15 | Nov 10 | ~2 wks after (Mar 15) |
Average dates based on 30-year NOAA climate normals. Individual years may vary ±2 weeks. Use the Zone Lookup Tool for ZIP-specific dates.
Duke's Top Tips for Washington Gardeners
- Seattle gardeners can transplant tomatoes in early May
- West of Cascades: cold cloudy summers — choose cold-tolerant tomato varieties
- East of Cascades (Spokane, Yakima): hot dry summers — great for warm-season crops
- Slugs are extremely heavy west of the Cascades — use iron phosphate bait
Common Challenges in Washington
- ⚠ Western WA cool cloudy summers limit tomato ripening
- ⚠ Slug pressure is intense in the wet western climate
- ⚠ East WA (Yakima, Spokane) has cold winters and late frosts
Best Crops for Washington
Get exact dates for your ZIP code in Washington
City averages are a starting point. Your actual microclimate matters — enter your ZIP for precise frost dates.
Frequently Asked Questions — Washington Gardening
What zone is Washington state?
Washington spans Zone 4b (high Cascades) to Zone 8b (Seattle area). Seattle is Zone 8b, Spokane is Zone 6a, Yakima is Zone 6a–7a, and Olympia is Zone 8a.
When to plant tomatoes in Seattle?
Start seeds indoors in late February. Transplant in early May with row covers, or mid-May safely. Choose cold-tolerant varieties like Siletz, Legend, or Willamette for the Pacific Northwest climate.