Annual Flower

When to Plant Nasturtiums in Washington

Edible flowers that double as pest traps. Plant near vegetables to lure aphids away from your food crops.

The Short Answer

Nasturtiums grow beautifully in western Washington — the cool maritime climate prevents the heat stress that shortens the season in southern states. They're one of the most reliable edible flowers for Puget Sound gardens.

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

Nasturtiums 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
2 wks before frost
Transplant Outside
1 wks after frost
Direct Sow
1 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
2 wks before frost
Transplant Outside
1 wks after frost
Direct Sow
1 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
2 wks before frost
Transplant Outside
1 wks after frost
Direct Sow
1 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
2 wks before frost
Transplant Outside
1 wks after frost
Direct Sow
1 wks after frost

Growing Nasturtiums in Washington

State-Specific Growing Tips

Western WA: sow from May. Nasturtiums produce well through the cool Puget Sound summer without bolting. Eastern WA: sow May through June. Poor soil, sun to partial shade.

Recommended Varieties for Washington

Jewel Mix, Alaska, Spitfire. Western WA's cool climate supports long-lasting nasturtium displays.

Common Challenges in Washington

Slugs on seedlings in western WA. Aphids (trap crop). Otherwise trouble-free.

Growing Tips

Both flowers and young leaves are edible with a peppery taste. Thrives in poor soil — too much nitrogen means all leaves, no flowers.

Companion Planting

Plant nasturtiums alongside these companions for better growth:

Tomatoes Cucumbers Squash Beans

The Bottom Line

Nasturtiums 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

Nasturtiums Growing Guide National planting guide with all states Washington Planting Calendar All plants for Washington Nasturtiums in Alabama Alabama planting dates Nasturtiums in Alaska Alaska planting dates Nasturtiums in Arizona Arizona planting dates Nasturtiums 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

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