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When to Plant Zucchini in Roscommon County, MI

Zucchini is an incredibly prolific summer squash that can produce an abundance of fruit from just a few plants. It is versatile in the kitchen from grilling to baking.

Roscommon County, Michigan is in USDA Zone 5a. The average last spring frost is May 15 and the first fall frost is October 2, giving you a growing season of approximately 140 days.

At an elevation of 1,298 feet, Roscommon County receives approximately 36 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Zucchini to ensure they mature before fall.

Roscommon County, MI (Zone 5a) Short season
140 days
Last Spring Frost May 15
140 growing days
First Fall Frost October 2

Roscommon County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (22 days to spare)
Start indoors: Apr 5 Transplant: May 24 🍅 Harvest: Jul 12 – Sep 6
Recommended (50%) ✓ Fits season (21 days to spare)
Start indoors: Apr 10 Transplant: May 29 🍅 Harvest: Jul 17 – Sep 11
Safe Start (90%) ✓ Fits season (24 days to spare)
Start indoors: Apr 26 Transplant: Jun 14 🍅 Harvest: Aug 2 – Sep 27

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
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Zucchini needs ~643 GDD — county provides 1,715 GDD Excellent fit

Zucchini Planting Timeline โ€” Roscommon County, MI

Zucchini Planting Calendar

Activity When Date Range
Start Indoors April 10 Apr 10 โ€“ Apr 24
Transplant Outdoors May 29 May 29 โ€“ Jun 12
Direct Sow May 22 May 22 โ€“ Jun 12
Harvest July 17 Jul 17 โ€“ Sep 11

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 Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

45โ€“60 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 5a

Growing Season

140 days

Growing Tips for Roscommon County

Direct sow after last frost. Harvest when fruits are 6-8 inches long for best flavor and texture. Check plants daily in summer as fruits can double in size overnight.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Zucchini in Roscommon County, MI?

Roscommon County is in Zone 5a with an average last frost of May 15. Plan your Zucchini planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Roscommon County, MI?

Roscommon County, Michigan is in USDA Hardiness Zone 5a. The average last spring frost is May 15 and first fall frost is October 2.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Roscommon County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

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 Roscommon County, MI. Local conditions may vary. Last updated: April 2026.