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When to Plant Eggplant in Knox County, OH

Knox County, Ohio Zone 6a May

Your May planting checklist for Knox County, Ohio

Each item below is timed to Knox County, Ohio's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 29
Avg. first frost October 15
Soil temp (4") 61°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Harden off and plant eggplant

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Sow eggplant where they'll grow

    Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.

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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.

Knox County, Ohio is in USDA Zone 6a. The average last spring frost is April 29 and the first fall frost is October 15, giving you a growing season of approximately 169 days.

At an elevation of 861 feet, Knox County receives approximately 33 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Eggplant during the growing season.

Knox County, OH (Zone 6a) Moderate season
169 days
Last Spring Frost April 29
169 growing days
First Fall Frost October 15

Knox County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (18 days to spare)
Start indoors: Feb 15 Transplant: May 10 🍅 Harvest: Jul 19 – Sep 20
Recommended (50%) ✓ Fits season (22 days to spare)
Start indoors: Feb 18 Transplant: May 13 🍅 Harvest: Jul 22 – Sep 23
Safe Start (90%) ✓ Fits season (17 days to spare)
Start indoors: Mar 7 Transplant: May 30 🍅 Harvest: Aug 8 – Oct 10

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 Knox County

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

Soil pH

Your soil pH (5.8–6.7) is within Eggplant's preferred range (5.5–7.0).

Soil Texture

The silt loam soil in Knox 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 (4.1%) — Eggplant will thrive.

How to Plant Eggplant

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

Succession Planting Eggplant

3
successive plantings in your 169-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
0.8″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 917 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 1.3" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 4.8" 3" 1.8" 💧 Light watering
May 4.8" 4.6" 0.2" 💧 Light watering
Jun 4.8" 3.7" 1.1" 💧 Light watering
Jul 4.8" 3.8" 1" 💧 Light watering
Aug 4.8" 3.2" 1.6" 💧 Light watering
Sep 4.8" 2.7" 2.1" 💧 Light watering
Oct 4.8" 2.6" 2.2" 💧 Light watering
Nov 2.1" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Knox 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 ~1,144 GDD — county provides 2,577 GDD Excellent fit

Eggplant Planting Timeline — Knox County, OH

Eggplant Planting Calendar

Activity When Date Range
Start Indoors February 18 Feb 18 – Mar 4
Transplant Outdoors May 13 May 13 – May 27
Direct Sow May 6 May 6 – May 27
Harvest July 22 Jul 22 – Sep 23

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April
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 6a

📆 Growing Season

169 days in Knox County

Growing Tips for Eggplant in Knox County

Direct sow Eggplant outdoors after April 29 in Knox 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 Knox County, OH?

Knox County is in Zone 6a with an average last frost of April 29. Plan your Eggplant planting based on this frost date — see the calendar above for exact timing.

What planting zone is Knox County, OH?

Knox County, Ohio is in USDA Hardiness Zone 6a. The average last spring frost is April 29 and first fall frost is October 15.

🌱

Your Knox County Garden Planner — Free

A 24-page printable planner built for Knox County (Zone 6a). 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 Knox County, OH. 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.