Blog

When to Plant Sweet Corn in Macomb County, MI

Sweet corn is bred for high sugar content in its kernels, which convert to starch rapidly after harvest. Modern supersweet varieties hold their sweetness longer.

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 Sweet Corn 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 (65 days to spare)
Transplant: Apr 26 🍅 Harvest: Jun 28 – Aug 9
Recommended (50%) ✓ Fits season (70 days to spare)
Transplant: Apr 28 🍅 Harvest: Jun 30 – Aug 11
Safe Start (90%) ✓ Fits season (66 days to spare)
Transplant: May 13 🍅 Harvest: Jul 15 – Aug 26

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
Sweet Corn needs ~1,369 GDD — county provides 3,193 GDD Excellent fit

Sweet Corn Planting Timeline โ€” Macomb County, MI

Sweet Corn Planting Calendar

Activity When Date Range
Direct Sow May 5 May 5 โ€“ May 26
Harvest July 7 Jul 7 โ€“ Aug 18

Plant 1" deep ยท 12" apart ยท Rows 36" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May Direct Sow
June โ€”
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

60โ€“90 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 6a

Growing Season

175 days

Growing Tips for Macomb County

Plant in blocks of at least 4 rows for wind pollination. Direct sow after soil is warm. Isolate supersweet varieties from other corn types to prevent cross-pollination.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Sweet Corn in Macomb County, MI?

Macomb County is in Zone 6a with an average last frost of April 28. Plan your Sweet Corn 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.