Warm-Season Vegetable

When to Plant Squash (Summer) in Oregon

Zucchini and yellow squash are the garden's most generous producers. You'll be sharing with neighbors by midsummer.

The Short Answer

In Oregon, squash (summer) planting dates vary by region. In Willamette Valley, your average last frost is around Mar 25 - Apr 15, while Southern Oregon Coast sees its last frost around Mar 5 - Mar 25. Since squash (summer) are frost-sensitive, start seeds indoors 3 weeks before your last frost, then transplant outside 2 weeks after frost danger has passed. Rich volcanic soils in Willamette Valley. Dry, alkaline soils east of Cascades. Acidic forest soils on coast. Generally...

Oregon Frost Dates

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

Region Zones Last Frost (Spring) First Frost (Fall)
Willamette Valley 8a, 8b Mar 25 - Apr 15 Oct 15 - Nov 10
Portland Metro 8b, 9a Mar 15 - Apr 5 Oct 25 - Nov 15
Central/Eastern Oregon 5a, 5b, 6a, 6b May 10 - Jun 1 Sep 10 - Oct 1
Southern Oregon Coast 8b, 9a, 9b Mar 5 - Mar 25 Nov 5 - Nov 25

Squash (Summer) Planting Schedule for Oregon

Willamette Valley (Zones 8a, 8b)

Average last frost: Mar 25 - Apr 15 · Average first frost: Oct 15 - Nov 10

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

Portland Metro (Zones 8b, 9a)

Average last frost: Mar 15 - Apr 5 · 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

Central/Eastern Oregon (Zones 5a, 5b, 6a, 6b)

Average last frost: May 10 - Jun 1 · Average first frost: Sep 10 - Oct 1

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

Southern Oregon Coast (Zones 8b, 9a, 9b)

Average last frost: Mar 5 - Mar 25 · Average first frost: Nov 5 - Nov 25

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

Growing Squash (Summer) in Oregon

Squash (Summer) in Oregon's Climate

Your long season supports both summer and winter squash without the season-length anxiety that northern growers face. Spring and fall plantings are both productive. Squash vine borer typically has two generations in warm climates — stagger plantings to ensure some production survives.

Soil Considerations for Oregon

Rich volcanic soils in Willamette Valley. Dry, alkaline soils east of Cascades. Acidic forest soils on coast. Generally excellent for gardening in valleys. Make sure soil has warmed to at least 60°F before planting squash (summer) outside.

Oregon Climate & Growing Season

Dramatic east-west climate divide. Wet, mild winters west of Cascades. Dry, cold winters east. Year-round gardening possible in mild western valleys. Squash (Summer) cannot tolerate any frost, so wait until all frost danger has passed before transplanting outside. Watch local forecasts carefully in spring.

Growing season length varies across Oregon: Willamette Valley (8a, 8b) has a last frost around Mar 25 - Apr 15, while Southern Oregon Coast (8b, 9a, 9b) sees frost end around Mar 5 - Mar 25. This difference matters for squash (summer) — transplant timing shifts by several weeks across the state.

Growing Tips

Harvest when fruits are 6-8 inches long for best flavor. Larger squash become seedy and tough.

Companion Planting

Plant squash (summer) alongside these companions for better growth:

Corn Beans Nasturtiums

Keep squash (summer) away from:

Potatoes

The Bottom Line

Squash (Summer) can be grown successfully across Oregon, but your exact planting dates depend on which region you're in. Willamette Valley gardeners should plan around a Mar 25 - Apr 15 last frost, while those in Southern Oregon Coast can typically plant earlier. For exact dates based on your zip code, use our free planting date finder.

Related Guides

Squash (Summer) Growing Guide National planting guide with all states Oregon Planting Calendar All plants for Oregon Squash (Summer) in Alabama Alabama planting dates Squash (Summer) in Alaska Alaska planting dates Squash (Summer) in Arizona Arizona planting dates Squash (Summer) 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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