Warm-Season Vegetable

When to Plant Corn (Sweet) in Washington

Nothing says summer like fresh sweet corn. Plant in blocks (not rows) for proper pollination.

The Short Answer

Eastern Washington grows spectacular sweet corn in its hot, irrigated valleys — the Yakima Valley and Columbia Basin produce ears that rival anything in the Midwest. Western Washington is a different story: the cool, cloudy Puget Sound climate makes corn a challenge, though it's not impossible with the right variety and the warmest garden spot. The key divide is heat accumulation — corn needs sustained warmth that western Washington struggles to provide consistently.

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

Corn (Sweet) 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

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

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

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

Direct Sow
2 wks after frost

Growing Corn (Sweet) in Washington

State-Specific Growing Tips

Eastern Washington: plant from mid-May and enjoy excellent conditions. Hot days, cool nights, and low humidity produce sweet, crisp ears with minimal pest pressure. Irrigation is essential — corn is water-hungry. Western Washington: plant from late May to early June in the warmest spot you can find. Choose early varieties (60-65 days) and hope for a warm summer. Black plastic mulch and a south-facing slope improve odds. Don't expect Midwest-sized ears, but you can get a modest harvest in good years. Blocks of at least 4×4 for pollination — even more important in western WA where plant spacing might be tight.

Recommended Varieties for Washington

Eastern Washington: any variety thrives. Silver Queen, Incredible, Honey Select, Peaches and Cream. Western Washington: early varieties only — Early Sunglow (63 days), Earlivee (58 days), Sugar Buns (72 days). If your western WA garden rarely tops 80°F, choose the shortest-maturity variety you can find.

Common Challenges in Washington

Eastern Washington: corn earworm arrives but is typically less severe than in southern states. Minimal disease thanks to dry climate. Raccoons in rural areas. Western Washington: insufficient heat is the fundamental challenge — cool summers may not produce pollination temperatures. Slugs damage seedlings. In good years, western WA corn is excellent; in cool years, ears may be stubby or have poor kernel fill.

Growing Tips

Plant in blocks of at least 4x4 for wind pollination. Corn is a heavy feeder — amend soil with compost before planting.

Companion Planting

Plant corn (sweet) alongside these companions for better growth:

Beans Squash Melons

Keep corn (sweet) away from:

Tomatoes

The Bottom Line

Corn (Sweet) 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

Corn (Sweet) Growing Guide National planting guide with all states Washington Planting Calendar All plants for Washington Corn (Sweet) in Alabama Alabama planting dates Corn (Sweet) in Alaska Alaska planting dates Corn (Sweet) in Arizona Arizona planting dates Corn (Sweet) 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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