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When to Plant Zucchini in Macomb 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.

Macomb County, Michigan is in USDA Zone 6a. The average last spring frost is April 28 and the first fall frost is October 20, giving you a growing season of approximately 175 days.

At an elevation of 628 feet, Macomb County receives approximately 33.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91ยฐF, providing good warmth for Zucchini during the growing season.

Macomb County, MI (Zone 6a) Moderate season
175 days
Last Spring Frost April 28
175 growing days
First Fall Frost October 20

Macomb County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (51 days to spare)
Start indoors: Mar 22 Transplant: May 10 🍅 Harvest: Jun 28 – Aug 23
Recommended (50%) ✓ Fits season (56 days to spare)
Start indoors: Mar 24 Transplant: May 12 🍅 Harvest: Jun 30 – Aug 25
Safe Start (90%) ✓ Fits season (52 days to spare)
Start indoors: Apr 8 Transplant: May 27 🍅 Harvest: Jul 15 – Sep 9

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
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 298 gal / 100 sq ft
Zucchini needs ~958 GDD — county provides 3,193 GDD Excellent fit

Zucchini Planting Timeline โ€” Macomb County, MI

Zucchini Planting Calendar

Activity When Date Range
Start Indoors March 24 Mar 24 โ€“ Apr 7
Transplant Outdoors May 12 May 12 โ€“ May 26
Direct Sow May 5 May 5 โ€“ May 26
Harvest June 30 Jun 30 โ€“ Aug 25

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 Transplant Outdoors Direct Sow
June Harvest
July Harvest
August Harvest
September โ€”
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 6a

Growing Season

175 days

Growing Tips for Macomb 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 Macomb County, MI?

Macomb County is in Zone 6a with an average last frost of April 28. Plan your Zucchini planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Macomb County, MI?

Macomb County, Michigan is in USDA Hardiness Zone 6a. The average last spring frost is April 28 and first fall frost is October 20.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Macomb County gardeners in Zone 6a 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 Macomb County, MI. Local conditions may vary. Last updated: April 2026.