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When to Plant Pumpkin in Keweenaw County, MI

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

Keweenaw County, Michigan is in USDA Zone 4a. The average last spring frost is May 19 and the first fall frost is October 1, giving you a growing season of approximately 135 days.

At an elevation of 1,035 feet, Keweenaw County receives approximately 40.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81ยฐF, so choose short-season varieties of Pumpkin to ensure they mature before fall.

Keweenaw County, MI (Zone 4a) Short season
135 days
Last Spring Frost May 19
135 growing days
First Fall Frost October 1

Keweenaw County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 3 Transplant: Jun 5 🍅 Harvest: Sep 4 – Oct 23
Recommended (50%) ✗ May not fit
Start indoors: Apr 7 Transplant: Jun 9 🍅 Harvest: Sep 8 – Oct 27
Safe Start (90%) ✗ May not fit
Start indoors: Apr 23 Transplant: Jun 25 🍅 Harvest: Sep 24 – Nov 12

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
1.3″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Pumpkin needs ~1,102 GDD — county provides 1,451 GDD Excellent fit

Pumpkin Planting Timeline โ€” Keweenaw County, MI

Pumpkin Planting Calendar

Activity When Date Range
Start Indoors April 7 Apr 7 โ€“ Apr 21
Transplant Outdoors June 9 Jun 9 โ€“ Jun 23
Direct Sow June 2 Jun 2 โ€“ Jun 23
Harvest September 8 Sep 8 โ€“ Oct 27

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Start Indoors
May โ€”
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

135 days

Growing Tips for Keweenaw 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 Keweenaw County, MI?

Keweenaw County is in Zone 4a with an average last frost of May 19. Plan your Pumpkin planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Keweenaw County, MI?

Keweenaw County, Michigan is in USDA Hardiness Zone 4a. The average last spring frost is May 19 and first fall frost is October 1.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Keweenaw 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 Keweenaw County, MI. Local conditions may vary. Last updated: April 2026.