Warm-Season Vegetable

When to Plant Cucumbers in Washington

Cool, crisp, and perfect for salads and pickling. Cucumbers thrive in warm weather and produce abundantly.

The Short Answer

Cucumbers are one of the more achievable warm-season crops in western Washington — they're easier than tomatoes and peppers because they grow fast enough to produce a harvest even in Puget Sound's moderate summer heat. Eastern Washington grows outstanding cucumbers in the irrigated valleys, where hot days and low humidity create near-perfect conditions with minimal disease pressure.

Washington Frost Dates

Your planting dates depend on which part of Washington you're in. Here are the frost date ranges by region:

Region Zones Last Frost (Spring) First Frost (Fall)
Western Washington (Seattle/Tacoma) 8a, 8b Mar 25 - Apr 15 Oct 25 - Nov 15
Puget Sound 8b, 9a Mar 15 - Apr 5 Nov 1 - Nov 20
Eastern Washington 5b, 6a, 6b, 7a Apr 25 - May 15 Sep 25 - Oct 15
Central Washington 6a, 6b, 7a Apr 20 - May 10 Oct 1 - Oct 20

Cucumbers Planting Schedule for Washington

Western Washington (Seattle/Tacoma) (Zones 8a, 8b)

Average last frost: Mar 25 - Apr 15 · Average first frost: Oct 25 - Nov 15

Start Seeds Indoors
3 wks before frost
Transplant Outside
2 wks after frost
Direct Sow
2 wks after frost

Puget Sound (Zones 8b, 9a)

Average last frost: Mar 15 - Apr 5 · Average first frost: Nov 1 - Nov 20

Start Seeds Indoors
3 wks before frost
Transplant Outside
2 wks after frost
Direct Sow
2 wks after frost

Eastern Washington (Zones 5b, 6a, 6b, 7a)

Average last frost: Apr 25 - May 15 · Average first frost: Sep 25 - Oct 15

Start Seeds Indoors
3 wks before frost
Transplant Outside
2 wks after frost
Direct Sow
2 wks after frost

Central Washington (Zones 6a, 6b, 7a)

Average last frost: Apr 20 - May 10 · Average first frost: Oct 1 - Oct 20

Start Seeds Indoors
3 wks before frost
Transplant Outside
2 wks after frost
Direct Sow
2 wks after frost

Growing Cucumbers in Washington

State-Specific Growing Tips

Western Washington: direct sow from early to mid-June when soil reaches 60°F. Start seeds indoors in late May for transplanting in mid-June — the 2-week head start matters in the Puget Sound region's compressed warm season. Black plastic mulch pre-warms soil effectively. Eastern Washington: direct sow from mid-May and enjoy fast, vigorous growth in the hot, dry conditions. In both regions, trellising improves production — in the west by warming fruits in the sun, in the east by keeping them off hot soil. WSU Extension's vegetable variety trials cover both sides of the Cascades.

Recommended Varieties for Washington

Western Washington: Marketmore 76, Diva, and Salad Bush (compact, 57 days) are reliable in the cooler Puget Sound climate. Japanese varieties like Tasty Green are productive in moderate heat. Eastern Washington: any variety thrives. Armenian cucumber, Persian/Beit Alpha types, and standard American slicers all produce abundantly in the Yakima and Columbia Valleys.

Common Challenges in Washington

In western Washington, slugs are the primary pest on young seedlings — protect with iron phosphate bait. Powdery mildew appears in late summer but is less aggressive than in the humid East. Cool nights can slow production but rarely stop it for cucumbers. In eastern Washington, spider mites are the main concern in hot, dry conditions. Cucumber beetles are uncommon in the Pacific Northwest — a significant advantage over eastern gardens. Bacterial wilt is rare west of the Rockies.

Growing Tips

Trellis for straighter fruits and better air circulation. Pick regularly to encourage more production.

Companion Planting

Plant cucumbers alongside these companions for better growth:

Beans Corn Peas Sunflowers

Keep cucumbers away from:

Potatoes Aromatic Herbs

The Bottom Line

Cucumbers can be grown successfully in Washington with proper attention to regional frost dates and local growing conditions. Timing varies across the state — Western Washington (Seattle/Tacoma) gardeners work with a last frost around Mar 25 - Apr 15, while Central Washington sees frost end around Apr 20 - May 10. Choose varieties suited to your region, amend your soil based on its specific needs, and monitor for the pests and diseases most common in your area. For exact dates based on your zip code, use our free planting date finder.

Related Guides

Cucumbers Growing Guide National planting guide with all states Washington Planting Calendar All plants for Washington Cucumbers in Alabama Alabama planting dates Cucumbers in Alaska Alaska planting dates Cucumbers in Arizona Arizona planting dates Cucumbers in Arkansas Arkansas planting dates
Note: All dates are based on NOAA 30-year Climate Normals and represent historical averages, not predictions for any specific year. Always check your local weather forecast before planting frost-sensitive crops. Learn about our data sources.

Last reviewed: March 29, 2026

Ready to Start Planting?

Enter your zip code and pick your plant. We'll tell you exactly when to plant, start seeds, and harvest — based on where you live.

Find Your Planting Dates