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When to Plant Squash (Winter) in Ontonagon County, MI

Winter squash includes butternut, acorn, delicata, and hubbard varieties grown to full maturity with hard rinds for storage. They develop sweet, dense flesh.

Ontonagon County, Michigan is in USDA Zone 4a. The average last spring frost is May 22 and the first fall frost is September 28, giving you a growing season of approximately 129 days.

At an elevation of 502 feet, Ontonagon County receives approximately 42 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80ยฐF, so choose short-season varieties of Squash (Winter) to ensure they mature before fall.

Ontonagon County, MI (Zone 4a) Short season
129 days
Last Spring Frost May 22
129 growing days
First Fall Frost September 28

Ontonagon County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.2

Drainage

Well Drained

Monthly Watering Guide for Squash (Winter)

Squash (Winter) needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Squash (Winter) Needs Rainfall You Supplement Action
Jan โ€” 2" 0" โ„๏ธ Dormant
Feb โ€” 2.1" 0" โ„๏ธ Dormant
Mar โ€” 2.8" 0" โ„๏ธ Dormant
Apr โ€” 4.4" 0" โ„๏ธ Dormant
May 4.3" 4.8" 0" โœ… Rainfall sufficient
Jun 4.3" 5.2" 0" โœ… Rainfall sufficient
Jul 4.3" 4.3" 0" โœ… Rainfall sufficient
Aug 4.3" 4.2" 0.1" ๐Ÿ’ง Light watering
Sep 4.3" 3.5" 0.8" ๐Ÿ’ง Light watering
Oct โ€” 3.6" 0" โ„๏ธ Dormant
Nov โ€” 2.6" 0" โ„๏ธ Dormant
Dec โ€” 2.4" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Ontonagon County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Squash (Winter) Planting Timeline โ€” Ontonagon County, MI

Squash (Winter) Planting Calendar

Activity When Date Range
Start Indoors April 10 Apr 10 โ€“ Apr 24
Transplant Outdoors June 12 Jun 12 โ€“ Jun 26
Direct Sow June 5 Jun 5 โ€“ Jun 26
Harvest September 4 Sep 4 โ€“ Oct 30

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

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

Moderate โ€” regular watering

๐Ÿ“… Days to Maturity

80โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: N/A

๐Ÿ—บ๏ธ USDA Zone

Zone 4a

๐Ÿ“† Growing Season

129 days in Ontonagon County

Growing Tips for Ontonagon County

Direct sow after last frost on rich mounds. Allow ample space for sprawling vines. Cure harvested fruits in the sun for 10 days before storing in a cool, dry place.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Squash (Winter) in Ontonagon County, MI?

Ontonagon County is in Zone 4a with an average last frost of May 22. Plan your Squash (Winter) planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Ontonagon County, MI?

Ontonagon County, Michigan is in USDA Hardiness Zone 4a. The average last spring frost is May 22 and first fall frost is September 28.

๐ŸŒฑ

Plan Your Garden with Confidence

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

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Free download. Plan your entire garden season in minutes.

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