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When to Plant Eggplant in Montmorency County, MI

Montmorency County, Michigan Zone 5a May

May in Montmorency County, Michigan — your action list

Welcome to May in Zone 5a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 19
Avg. first frost October 1
Soil temp (4") 52°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
  1. Put eggplant seeds straight in the ground

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

Looking ahead to June
  • Transplants going out: eggplant

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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.

Montmorency County, Michigan is in USDA Zone 5a. The average last spring frost is May 19 and the first fall frost is October 1, giving you a growing season of approximately 135 days.

At an elevation of 1,107 feet, Montmorency County receives approximately 40.5 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.

Montmorency County, MI (Zone 5a) Short season
135 days
Last Spring Frost May 19
135 growing days
First Fall Frost October 1

Montmorency County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 6 Transplant: May 29 🍅 Harvest: Aug 7 – Oct 9
Recommended (50%) ✗ May not fit
Start indoors: Mar 10 Transplant: Jun 2 🍅 Harvest: Aug 11 – Oct 13
Safe Start (90%) ✗ May not fit
Start indoors: Mar 24 Transplant: Jun 16 🍅 Harvest: Aug 25 – Oct 27

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 Montmorency County

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

Soil pH

Your soil pH (6.1–6.8) is within Eggplant's preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — Eggplant will thrive.

How to Plant Eggplant

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

Succession Planting Eggplant

2
successive plantings in your 135-day season

Sow every 7.4 weeks. Last sowing by Jul 08 to harvest before frost.

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
1.3″/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 1.8" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 4.1" 0" ❄️ Dormant
May 4.8" 4.3" 0.5" 💧 Light watering
Jun 4.8" 5.6" 0" ✅ Rainfall sufficient
Jul 4.8" 4.2" 0.6" 💧 Light watering
Aug 4.8" 4.7" 0.1" 💧 Light watering
Sep 4.8" 3.4" 1.4" 💧 Light watering
Oct 4.8" 3.2" 1.6" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Montmorency 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 1,653 GDD Excellent fit

Eggplant Planting Timeline — Montmorency County, MI

Eggplant Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 – Mar 24
Transplant Outdoors June 2 Jun 2 – Jun 16
Direct Sow May 26 May 26 – Jun 16
Harvest August 11 Aug 11 – Oct 13

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

Month-by-Month Timeline

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

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 5a

📆 Growing Season

135 days in Montmorency County

Growing Tips for Eggplant in Montmorency County

Direct sow Eggplant outdoors after May 19 in Montmorency 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 Montmorency County, MI?

Montmorency County is in Zone 5a with an average last frost of May 19. Plan your Eggplant planting based on this frost date — see the calendar above for exact timing.

What planting zone is Montmorency County, MI?

Montmorency County, Michigan is in USDA Hardiness Zone 5a. The average last spring frost is May 19 and first fall frost is October 1.

🌱

Your Montmorency County Garden Planner — Free

A 24-page printable planner built for Montmorency County (Zone 5a). 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 Montmorency 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.