Warm-Season Vegetable

When to Plant Pumpkins in Idaho

From jack-o-lanterns to pies, pumpkins need space and time but deliver a uniquely satisfying harvest.

The Short Answer

In Idaho, pumpkins 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 pumpkins 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

Pumpkins 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 Pumpkins in Idaho

Pumpkins in Idaho's Climate

Pumpkin growing is a calendar countdown — count backward from your target harvest date (usually mid-October for Halloween) using your variety's days-to-maturity. In short-season zones, choose 90-day varieties and start seeds indoors 3 weeks before last frost. Black plastic mulch warms soil for earlier transplanting. Squash vine borer is less common in cold zones — a genuine advantage.

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 65°F before planting pumpkins outside.

Idaho Climate & Growing Season

Arid climate. Low humidity. Hot days and cool nights. Irrigation essential. Short season at higher elevations. Pumpkins 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 pumpkins — transplant timing shifts by several weeks across the state.

Growing Tips

Count backwards from when you want ripe pumpkins (usually October). They need 90-120 days, so mid-June to early July is often ideal.

Companion Planting

Plant pumpkins alongside these companions for better growth:

Corn Beans Marigolds

Keep pumpkins away from:

Potatoes

The Bottom Line

Pumpkins 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

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