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When to Plant Eggplant in Calhoun County, MI

Calhoun County, Michigan Zone 6a May

May to-do list for Calhoun County, Michigan

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 30
Avg. first frost October 13
Soil temp (4") 58°F
Watering Low
Pest pressure Low
Daylight 14.4 hrs
  1. Plant out eggplant

    Your last frost (April 30) has passed. These warm-season crops can handle outdoor soil now.

  2. Direct-sow eggplant

    These tolerate cool soil, so you're not gambling by sowing now.

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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.

Calhoun County, Michigan is in USDA Zone 6a. The average last spring frost is April 30 and the first fall frost is October 13, giving you a growing season of approximately 166 days.

At an elevation of 1,242 feet, Calhoun County receives approximately 39.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Eggplant to ensure they mature before fall.

Calhoun County, MI (Zone 6a) Moderate season
166 days
Last Spring Frost April 30
166 growing days
First Fall Frost October 13
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Calhoun County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Feb 16 Transplant: May 11 🍅 Harvest: Jul 20 – Sep 21
Recommended (50%) ✓ Fits season (19 days to spare)
Start indoors: Feb 19 Transplant: May 14 🍅 Harvest: Jul 23 – Sep 24
Safe Start (90%) ✓ Fits season (13 days to spare)
Start indoors: Mar 9 Transplant: Jun 1 🍅 Harvest: Aug 10 – Oct 12

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.

Soil Compatibility in Calhoun County

How your county's soil matches Eggplant's growing requirements.

Soil pH

Your soil pH (6.0–6.9) is within Eggplant's preferred range (5.5–7.0).

Soil Texture

The silt loam soil in Calhoun County is excellent for Eggplant — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.0%) — Eggplant will thrive.

How to Plant Eggplant

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Succession Planting Eggplant

2
successive plantings in your 166-day season

Sow every 7.4 weeks. Last sowing by Jul 20 to harvest before frost.

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
1.0″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 149 gal / 100 sq ft

Monthly Watering Guide for Eggplant

Eggplant needs approximately 1.1 inches of water per week (4.8" per month). Here's how your county's rainfall compares month by month.

Month Eggplant Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 4.8" 3.6" 1.2" 💧 Light watering
May 4.8" 4.7" 0.1" 💧 Light watering
Jun 4.8" 5.4" 0" ✅ Rainfall sufficient
Jul 4.8" 4.4" 0.4" 💧 Light watering
Aug 4.8" 4" 0.8" 💧 Light watering
Sep 4.8" 4" 0.8" 💧 Light watering
Oct 4.8" 3" 1.8" 💧 Light watering
Nov 2.4" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Calhoun County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Eggplant Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Eggplant needs ~919 GDD — county provides 2,033 GDD Excellent fit

Eggplant Planting Timeline — Calhoun County, MI

Eggplant Planting Calendar

Activity When Date Range
Start Indoors February 19 Feb 19 – Mar 5
Transplant Outdoors May 14 May 14 – May 28
Direct Sow May 7 May 7 – May 28
Harvest July 23 Jul 23 – Sep 24

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.1"/week · Only during dry spells

📅 Days to Maturity

65–85 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

166 days in Calhoun County

Growing Tips for Eggplant in Calhoun County

Direct sow Eggplant outdoors after April 30 in Calhoun County when soil has warmed and frost danger has passed.

Common pests for Eggplant in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Eggplant in Calhoun County, MI?

Calhoun County is in Zone 6a with an average last frost of April 30. Plan your Eggplant planting based on this frost date — see the calendar above for exact timing.

What planting zone is Calhoun County, MI?

Calhoun County, Michigan is in USDA Hardiness Zone 6a. The average last spring frost is April 30 and first fall frost is October 13.

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Your Calhoun County Garden Planner — Free

A 24-page printable planner built for Calhoun County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Calhoun County, MI. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.