When to Plant Sweet Corn in Mackinac 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.
Mackinac County, Michigan is in USDA Zone 4b. The average last spring frost is May 12 and the first fall frost is October 10, giving you a growing season of approximately 151 days.
At an elevation of 1,335 feet, Mackinac County receives approximately 35.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Sweet Corn to ensure they mature before fall.
Mackinac County Soil Profile
Soil Type
Silt Loam
Soil pH
6.2-6.9
Drainage
Well Drained
Plant Planting Risk Windows
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
Sweet Corn Planting Timeline — Mackinac County, MI
Sweet Corn Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | May 26 | May 26 – Jun 16 |
| Harvest | July 28 | Jul 28 – Sep 8 |
Plant 1" deep · 12" apart · Rows 36" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Direct Sow |
| June | Direct Sow |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Moderate — regular watering
Days to Maturity
60–90 days
Soil pH
6 – 7
USDA Zone
Zone 4b
Growing Season
151 days
Growing Tips for Mackinac 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
Level Up Your Garden
Sweet Corn in Other Locations
Frequently Asked Questions
When should I plant Sweet Corn in Mackinac County, MI?
Mackinac County is in Zone 4b with an average last frost of May 12. Plan your Sweet Corn planting based on this frost date — see the calendar above for exact timing.
What planting zone is Mackinac County, MI?
Mackinac County, Michigan is in USDA Hardiness Zone 4b. The average last spring frost is May 12 and first fall frost is October 10.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Mackinac County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.
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