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When to plant Eggplant in Lee County, IL

Eggplant planted in Lee County between April 29 and May 20 matures in 65–85 days — well before the October 14 first frost.

When to Plant Eggplant in Lee County, IL

Eggplant
Lee County, Illinois Zone 5b June

What to do in June

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Lee County, Illinois.

Avg. last frost April 22
Avg. first frost October 14
Soil temp (4") 69°F
Watering Low
Pest pressure High
Daylight 15 hrs
To set up a strong July, finish these tasks
  • Starting indoors: eggplant
  • First harvests: 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.

Lee County, Illinois is in USDA Zone 5b. The average last spring frost is April 22 and the first fall frost is October 14, giving you a growing season of approximately 175 days.

At an elevation of 1,010 feet, Lee County receives approximately 33.6 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.

Lee County, IL (Zone 5b) Moderate season
175 days
Last Spring Frost April 22
175 growing days
First Fall Frost October 14

Lee County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.9

Drainage

Well Drained

Eggplant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (29 days to spare)
Start indoors: Feb 6 Transplant: May 1 🍅 Harvest: Jul 10 – Sep 11
Recommended (50%) ✓ Fits season (28 days to spare)
Start indoors: Feb 11 Transplant: May 6 🍅 Harvest: Jul 15 – Sep 16
Safe Start (90%) ✓ Fits season (29 days to spare)
Start indoors: Feb 24 Transplant: May 19 🍅 Harvest: Jul 28 – Sep 29

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 Lee County

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

Soil pH

Your soil pH (6.3–6.9) is within Eggplant's preferred range (5.5–7.0).

Soil Texture

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

Drainage

Drainage is adequate for Eggplant.

Organic Matter

Organic matter is excellent (4.8%) — 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 21 to harvest before frost.

Eggplant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.8″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,166 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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" 0" ❄️ Dormant
Apr 4.8" 2.8" 2" 💧 Light watering
May 4.8" 4.4" 0.4" 💧 Light watering
Jun 4.8" 4.2" 0.6" 💧 Light watering
Jul 4.8" 3.3" 1.5" 💧 Light watering
Aug 4.8" 3.5" 1.3" 💧 Light watering
Sep 4.8" 2.9" 1.9" 💧 Light watering
Oct 4.8" 2.7" 2.1" 💧 Light watering
Nov 2.7" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Lee 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 2,275 GDD Excellent fit

Eggplant Planting Timeline — Lee County, IL

Eggplant Planting Calendar

Activity When Date Range
Start Indoors February 11 Feb 11 – Feb 25
Transplant Outdoors May 6 May 6 – May 20
Direct Sow April 29 Apr 29 – May 20
Harvest July 15 Jul 15 – Sep 16

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.1"/week · 2-3 times/week

📅 Days to Maturity

65–85 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

175 days in Lee County

Growing Tips for Eggplant in Lee County

Direct sow Eggplant outdoors after April 22 in Lee 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 Lee County, IL?

Lee County is in Zone 5b with an average last frost of April 22. Plan your Eggplant planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lee County, IL?

Lee County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 22 and first fall frost is October 14.

When should I plant Eggplant in Lee County, IL?

In Lee County, IL, plant Eggplant after the last frost (around April 22) and before the first frost (around October 14). Best results when soil holds above 50°F.

What growing zone is Lee County, IL for Eggplant?

Lee County sits in USDA Zone 5b. Eggplant grows reliably in zones 5a through 11b, so it's a good fit here.

Can Eggplant grow in Lee County's climate?

Yes — Eggplant grows well in Lee County's temperate climate. Lee County averages a 175-day frost-free season, with last frost around April 22 and first frost around October 14.

🌱

Your Lee County Garden Planner — Free

A 22-page printable planner built for Lee County (Zone 5b). 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 Lee County, IL. Local conditions may vary. Last updated: June 2026.

Sources & credits

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