Blog

When to Plant Eggplant in Marshall County, IL

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.

Marshall County, Illinois is in USDA Zone 5a. The average last spring frost is April 21 and the first fall frost is October 13, giving you a growing season of approximately 175 days.

At an elevation of 1,177 feet, Marshall County receives approximately 30.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Eggplant to ensure they mature before fall.

Marshall County, IL (Zone 5a) Moderate season
175 days
Last Spring Frost April 21
175 growing days
First Fall Frost October 13

Marshall County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (28 days to spare)
Start indoors: Feb 5 Transplant: Apr 30 🍅 Harvest: Jul 9 – Sep 10
Recommended (50%) ✓ Fits season (28 days to spare)
Start indoors: Feb 10 Transplant: May 5 🍅 Harvest: Jul 14 – Sep 15
Safe Start (90%) ✓ Fits season (25 days to spare)
Start indoors: Feb 28 Transplant: May 23 🍅 Harvest: Aug 1 – Oct 3

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 Marshall County

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

Soil pH

Your soil pH (6.0โ€“6.8) is within Eggplant's preferred range (5.5โ€“7.0).

Soil Texture

The silt loam soil in Marshall County is excellent for Eggplant โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.2%) โ€” Eggplant will thrive.

How to Plant Eggplant

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

Succession Planting Eggplant

3
successive plantings in your 175-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
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 692 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Eggplant needs ~975 GDD — county provides 2,275 GDD Excellent fit

Eggplant Planting Timeline โ€” Marshall County, IL

Eggplant Planting Calendar

Activity When Date Range
Start Indoors February 10 Feb 10 โ€“ Feb 24
Transplant Outdoors May 5 May 5 โ€“ May 19
Direct Sow April 28 Apr 28 โ€“ May 19
Harvest July 14 Jul 14 โ€“ Sep 15

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

65โ€“85 days

๐Ÿงช Soil pH

Needs 5.5โ€“7 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

175 days in Marshall County

Growing Tips for Eggplant in Marshall County

Direct sow Eggplant outdoors after April 21 in Marshall 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

Level Up Your Garden

Frequently Asked Questions

When should I plant Eggplant in Marshall County, IL?

Marshall County is in Zone 5a with an average last frost of April 21. Plan your Eggplant planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Marshall County, IL?

Marshall County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 21 and first fall frost is October 13.

๐ŸŒฑ

Plan Your Garden with Confidence

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

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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