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When to Plant Eggplant in Ottawa County, MI

Ottawa County, Michigan Zone 6a May

This month in Ottawa County, Michigan

Welcome to May in Zone 6a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 9
Avg. first frost October 9
Soil temp (4") 57°F
Watering Low
Pest pressure Low
Daylight 14.5 hrs
  1. Time to transplant eggplant

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

  2. Scatter eggplant into prepared beds

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

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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.

Ottawa County, Michigan is in USDA Zone 6a. The average last spring frost is May 9 and the first fall frost is October 9, giving you a growing season of approximately 153 days.

At an elevation of 1,027 feet, Ottawa County receives approximately 41.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Eggplant to ensure they mature before fall.

Ottawa County, MI (Zone 6a) Moderate season
153 days
Last Spring Frost May 9
153 growing days
First Fall Frost October 9
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Ottawa County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (11 days to spare)
Start indoors: Feb 18 Transplant: May 13 🍅 Harvest: Jul 22 – Sep 23
Recommended (50%) ✓ Fits season (6 days to spare)
Start indoors: Feb 28 Transplant: May 23 🍅 Harvest: Aug 1 – Oct 3
Safe Start (90%) ✓ Fits season (2 days to spare)
Start indoors: Mar 20 Transplant: Jun 12 🍅 Harvest: Aug 21 – Oct 23

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 Ottawa County

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

Soil pH

Your soil pH (5.8–6.8) is within Eggplant's preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.5%) — Eggplant will thrive.

How to Plant Eggplant

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

Succession Planting Eggplant

2
successive plantings in your 153-day season

Sow every 7.4 weeks. Last sowing by Jul 16 to harvest before frost.

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 1.9" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 4.1" 0" ❄️ Dormant
May 4.8" 4.7" 0.1" 💧 Light watering
Jun 4.8" 5.8" 0" ✅ Rainfall sufficient
Jul 4.8" 5.1" 0" ✅ Rainfall sufficient
Aug 4.8" 4.4" 0.4" 💧 Light watering
Sep 4.8" 3.2" 1.6" 💧 Light watering
Oct 4.8" 3" 1.8" 💧 Light watering
Nov 2.9" 0" ❄️ Dormant
Dec 2.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Ottawa 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 ~975 GDD — county provides 1,989 GDD Excellent fit

Eggplant Planting Timeline — Ottawa County, MI

Eggplant Planting Calendar

Activity When Date Range
Start Indoors February 28 Feb 28 – Mar 14
Transplant Outdoors May 23 May 23 – Jun 6
Direct Sow May 16 May 16 – Jun 6
Harvest August 1 Aug 1 – Oct 3

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 Transplant Outdoors Direct Sow
July
August Harvest
September Harvest
October Harvest
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.1"/week · Natural rainfall sufficient

📅 Days to Maturity

65–85 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

153 days in Ottawa County

Growing Tips for Eggplant in Ottawa County

Direct sow Eggplant outdoors after May 09 in Ottawa 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 Ottawa County, MI?

Ottawa County is in Zone 6a with an average last frost of May 9. Plan your Eggplant planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ottawa County, MI?

Ottawa County, Michigan is in USDA Hardiness Zone 6a. The average last spring frost is May 9 and first fall frost is October 9.

🌱

Your Ottawa County Garden Planner — Free

A 24-page printable planner built for Ottawa 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 Ottawa 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.