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When to Plant Eggplant in Iosco County, MI

Eggplant is a heat-loving solanaceous crop that produces glossy fruits in purple, white, or striped varieties. It requires long, warm growing seasons for best production.

Iosco County, Michigan is in USDA Zone 5a. The average last spring frost is May 14 and the first fall frost is October 3, giving you a growing season of approximately 142 days.

At an elevation of 696 feet, Iosco County receives approximately 37.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88ยฐF, providing good warmth for Eggplant during the growing season.

Iosco County, MI (Zone 5a) Short season
142 days
Last Spring Frost May 14
142 growing days
First Fall Frost October 3

Iosco County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 27 Transplant: May 22 🍅 Harvest: Jul 31 – Oct 2
Recommended (50%) ✗ May not fit
Start indoors: Mar 5 Transplant: May 28 🍅 Harvest: Aug 6 – Oct 8
Safe Start (90%) ✗ May not fit
Start indoors: Mar 19 Transplant: Jun 11 🍅 Harvest: Aug 20 – Oct 22

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
Eggplant needs ~1,200 GDD — county provides 2,272 GDD Excellent fit

Eggplant Planting Timeline โ€” Iosco County, MI

Eggplant Planting Calendar

Activity When Date Range
Start Indoors March 5 Mar 5 โ€“ Mar 19
Transplant Outdoors May 28 May 28 โ€“ Jun 11
Direct Sow May 21 May 21 โ€“ Jun 11
Harvest August 6 Aug 6 โ€“ Oct 8

Plant 1" deep ยท 30" apart ยท Rows 42" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April โ€”
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July โ€”
August Harvest
September Harvest
October Harvest
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

65โ€“85 days

Soil pH

5.5 โ€“ 7

USDA Zone

Zone 5a

Growing Season

142 days

Growing Tips for Iosco County

Start seeds indoors 8-10 weeks before last frost. Transplant only after nighttime temperatures stay above 55F. Mulch to retain moisture and warmth around roots.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel
  • Kohlrabi

Level Up Your Garden

Frequently Asked Questions

When should I plant Eggplant in Iosco County, MI?

Iosco County is in Zone 5a with an average last frost of May 14. Plan your Eggplant planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Iosco County, MI?

Iosco County, Michigan is in USDA Hardiness Zone 5a. The average last spring frost is May 14 and first fall frost is October 3.

๐ŸŒฑ

Plan Your Garden with Confidence

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

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