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When to plant Eggplant in Alexander County County,

Alexander County County gardeners should plant Eggplant between April 17 and May 8 in spring. With Alexander County County's Zone 7a climate (last frost April 10), Eggplant needs 85 days to mature — plant by July 28 for a full harvest.

When to Plant Eggplant in Alexander County, IL

Eggplant
Alexander County, Illinois Zone 7a June

June to-do list for Alexander County, Illinois

If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 10
Avg. first frost October 21
Soil temp (4") 77°F
Watering Low
Pest pressure High
Daylight 14.5 hrs
  1. Begin indoor sowing: eggplant

    You're about 18 weeks out from your last frost — the perfect window to get these germinating indoors.

Before July arrives, get these ready
  • 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.

Alexander County, Illinois is in USDA Zone 7a. The average last spring frost is April 10 and the first fall frost is October 21, giving you a growing season of approximately 194 days.

At an elevation of 1,260 feet, Alexander County receives approximately 38.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Eggplant during the growing season.

Alexander County, IL (Zone 7a) Moderate season
194 days
Last Spring Frost April 10
194 growing days
First Fall Frost October 21

Alexander County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7

Drainage

Well Drained

Eggplant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (45 days to spare)
Start indoors: Feb 1 Transplant: Apr 19 🍅 Harvest: Jun 28 – Aug 30
Recommended (50%) ✓ Fits season (47 days to spare)
Start indoors: Feb 6 Transplant: Apr 24 🍅 Harvest: Jul 3 – Sep 4
Safe Start (90%) ✓ Fits season (45 days to spare)
Start indoors: Feb 20 Transplant: May 8 🍅 Harvest: Jul 17 – Sep 18

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 Alexander County

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

Soil pH

Your soil pH (5.9–7.0) is within Eggplant's preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (4.0%). Annual compost additions will help Eggplant.

How to Plant Eggplant

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

Succession Planting Eggplant

3
successive plantings in your 194-day season

Sow every 7.4 weeks. Last sowing by Jul 28 to harvest before frost.

Eggplant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.8″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 548 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 3" 0" ❄️ Dormant
Apr 4.8" 4.3" 0.5" 💧 Light watering
May 4.8" 4.1" 0.7" 💧 Light watering
Jun 4.8" 5.1" 0" ✅ Rainfall sufficient
Jul 4.8" 3.8" 1" 💧 Light watering
Aug 4.8" 4.8" 0" ✅ Rainfall sufficient
Sep 4.8" 3" 1.8" 💧 Light watering
Oct 4.8" 3" 1.8" 💧 Light watering
Nov 2.4" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Alexander 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 ~1,200 GDD — county provides 3,104 GDD Excellent fit

Eggplant Planting Timeline — Alexander County, IL

Eggplant Planting Calendar

Activity When Date Range
Start Indoors February 6 Feb 6 – Feb 20
Transplant Outdoors April 24 Apr 24 – May 8
Direct Sow April 17 Apr 17 – May 8
Harvest July 3 Jul 3 – Sep 4

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March
April Transplant Outdoors 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 · 1-2 times/week

📅 Days to Maturity

65–85 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 7a

📆 Growing Season

194 days in Alexander County

Growing Tips for Eggplant in Alexander County

Direct sow Eggplant outdoors after April 10 in Alexander 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 Alexander County, IL?

Alexander County is in Zone 7a with an average last frost of April 10. Plan your Eggplant planting based on this frost date — see the calendar above for exact timing.

What planting zone is Alexander County, IL?

Alexander County, Illinois is in USDA Hardiness Zone 7a. The average last spring frost is April 10 and first fall frost is October 21.

When should I plant Eggplant in Alexander County County, ?

In Alexander County County, , plant Eggplant after the last frost (around April 10) and before the first frost (around October 21). Best results when soil holds above 50°F.

What growing zone is Alexander County County, for Eggplant?

Alexander County County sits in USDA Zone 7a. Eggplant grows reliably in zones 5a through 11b, so it's a good fit here.

Can Eggplant grow in Alexander County County's climate?

Yes — Eggplant grows well in Alexander County County's temperate climate. Alexander County County averages a 194-day frost-free season, with last frost around April 10 and first frost around October 21.

🌱

Your Alexander County Garden Planner — Free

A 22-page printable planner built for Alexander County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Alexander 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.