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When to Plant Pumpkin in Chouteau County, MT

Pumpkins are large-fruited squash varieties grown for eating, decoration, and seed production. They require ample space and a long, warm growing season.

Chouteau County, Montana is in USDA Zone 4a. The average last spring frost is May 12 and the first fall frost is September 27, giving you a growing season of approximately 138 days.

At an elevation of 5,753 feet, Chouteau County receives approximately 15 inches of rainfall annually with predominantly loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Pumpkin to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Pumpkin successfully. Mulch heavily to conserve soil moisture.

Chouteau County, MT (Zone 4a) Short season
138 days
Last Spring Frost May 12
138 growing days
First Fall Frost September 27

Chouteau County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 27 Transplant: May 29 🍅 Harvest: Aug 28 – Oct 16
Recommended (50%) ✗ May not fit
Start indoors: Mar 31 Transplant: Jun 2 🍅 Harvest: Sep 1 – Oct 20
Safe Start (90%) ✗ May not fit
Start indoors: Apr 21 Transplant: Jun 23 🍅 Harvest: Sep 22 – Nov 10

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 801 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Pumpkin needs ~1,332 GDD — county provides 1,794 GDD Excellent fit

Pumpkin Planting Timeline โ€” Chouteau County, MT

Pumpkin Planting Calendar

Activity When Date Range
Start Indoors March 31 Mar 31 โ€“ Apr 14
Transplant Outdoors June 2 Jun 2 โ€“ Jun 16
Direct Sow May 26 May 26 โ€“ Jun 16
Harvest September 1 Sep 1 โ€“ Oct 20

Plant 1" deep ยท 30" apart ยท Rows 42" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April Start Indoors
May Direct Sow
June Transplant Outdoors Direct Sow
July โ€”
August โ€”
September Harvest
October Harvest
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

85โ€“120 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 4a

Growing Season

138 days

Growing Tips for Chouteau County

Direct sow on mounds after last frost. Allow 6-10 feet between plants. Slip a board under developing fruit to prevent rot. Harvest when rind is hard and deep in color.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Pumpkin in Chouteau County, MT?

Chouteau County is in Zone 4a with an average last frost of May 12. Plan your Pumpkin planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Chouteau County, MT?

Chouteau County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is May 12 and first fall frost is September 27.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Chouteau County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Chouteau County, MT. Local conditions may vary. Last updated: April 2026.