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When to Plant Eggplant in Tazewell 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.

Tazewell County, Illinois is in USDA Zone 5b. The average last spring frost is April 19 and the first fall frost is October 15, giving you a growing season of approximately 179 days.

At an elevation of 1,006 feet, Tazewell County receives approximately 40 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87ยฐF, providing good warmth for Eggplant during the growing season.

Tazewell County, IL (Zone 5b) Moderate season
179 days
Last Spring Frost April 19
179 growing days
First Fall Frost October 15

Tazewell County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (31 days to spare)
Start indoors: Feb 3 Transplant: Apr 28 🍅 Harvest: Jul 7 – Sep 8
Recommended (50%) ✓ Fits season (32 days to spare)
Start indoors: Feb 8 Transplant: May 3 🍅 Harvest: Jul 12 – Sep 13
Safe Start (90%) ✓ Fits season (31 days to spare)
Start indoors: Feb 22 Transplant: May 17 🍅 Harvest: Jul 26 – Sep 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 Tazewell County

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

Soil pH

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

Soil Texture

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

Organic Matter

Organic matter is excellent (4.0%) 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 179-day season

Sow every 7.4 weeks. Last sowing by Jul 22 to harvest before frost.

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 257 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 โ€” 1.9" 0" โ„๏ธ Dormant
Feb โ€” 1.7" 0" โ„๏ธ Dormant
Mar โ€” 2.6" 0" โ„๏ธ Dormant
Apr 4.8" 3.9" 0.9" ๐Ÿ’ง Light watering
May 4.8" 5.2" 0" โœ… Rainfall sufficient
Jun 4.8" 5.1" 0" โœ… Rainfall sufficient
Jul 4.8" 3.9" 0.9" ๐Ÿ’ง Light watering
Aug 4.8" 4.7" 0.1" ๐Ÿ’ง Light watering
Sep 4.8" 3.3" 1.5" ๐Ÿ’ง Light watering
Oct 4.8" 3.1" 1.7" ๐Ÿ’ง Light watering
Nov โ€” 2.6" 0" โ„๏ธ Dormant
Dec โ€” 1.9" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Tazewell County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~1,144 GDD — county provides 2,729 GDD Excellent fit

Eggplant Planting Timeline โ€” Tazewell County, IL

Eggplant Planting Calendar

Activity When Date Range
Start Indoors February 8 Feb 8 โ€“ Feb 22
Transplant Outdoors May 3 May 3 โ€“ May 17
Direct Sow April 26 Apr 26 โ€“ May 17
Harvest July 12 Jul 12 โ€“ Sep 13

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 Only during dry spells

๐Ÿ“… Days to Maturity

65โ€“85 days

๐Ÿงช Soil pH

Needs 5.5โ€“7 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

179 days in Tazewell County

Growing Tips for Eggplant in Tazewell County

Direct sow Eggplant outdoors after April 19 in Tazewell 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 Tazewell County, IL?

Tazewell County is in Zone 5b with an average last frost of April 19. Plan your Eggplant planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Tazewell County, IL?

Tazewell County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 19 and first fall frost is October 15.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Tazewell County gardeners in Zone 5b 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 Tazewell County, IL. Local conditions may vary. Last updated: April 2026.