Warm-Season Vegetable

When to Plant Squash (Summer) in Idaho

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

The Short Answer

In Idaho, squash (summer) planting dates vary by region. In Northern Idaho, your average last frost is around May 5 - May 25, while Eastern Idaho sees its last frost around May 20 - Jun 10. 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. Volcanic ash soils in south — excellent for gardening. Rocky soils in mountains. Alkaline in many areas.

Idaho Frost Dates

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

Region Zones Last Frost (Spring) First Frost (Fall)
Northern Idaho 5a, 5b, 6a May 5 - May 25 Sep 15 - Oct 5
Boise Area 6b, 7a Apr 20 - May 5 Oct 5 - Oct 20
Eastern Idaho 3b, 4a, 4b, 5a May 20 - Jun 10 Sep 1 - Sep 20

Squash (Summer) Planting Schedule for Idaho

Northern Idaho (Zones 5a, 5b, 6a)

Average last frost: May 5 - May 25 · Average first frost: Sep 15 - Oct 5

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

Boise Area (Zones 6b, 7a)

Average last frost: Apr 20 - May 5 · Average first frost: Oct 5 - Oct 20

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

Eastern Idaho (Zones 3b, 4a, 4b, 5a)

Average last frost: May 20 - Jun 10 · Average first frost: Sep 1 - Sep 20

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

Growing Squash (Summer) in Idaho

Squash (Summer) in Idaho's Climate

Summer squash (zucchini, yellow squash) is one of the most productive crops for short-season gardens — 45-60 day maturity means even 100-day seasons produce abundant harvests. Direct sow after soil reaches 60°F. Two or three plants produce more squash than most families can eat. Squash vine borer is less prevalent in cold zones, reducing the most frustrating squash pest.

Soil Considerations for Idaho

Volcanic ash soils in south — excellent for gardening. Rocky soils in mountains. Alkaline in many areas. Make sure soil has warmed to at least 60°F before planting squash (summer) outside.

Idaho Climate & Growing Season

Arid climate. Low humidity. Hot days and cool nights. Irrigation essential. Short season at higher elevations. 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 Idaho: Northern Idaho (5a, 5b, 6a) has a last frost around May 5 - May 25, while Eastern Idaho (3b, 4a, 4b, 5a) sees frost end around May 20 - Jun 10. 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 Idaho, but your exact planting dates depend on which region you're in. Northern Idaho gardeners should plan around a May 5 - May 25 last frost, while those in Eastern Idaho can typically plant later. 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 Idaho Planting Calendar All plants for Idaho 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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