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When to Plant Eggplant in Coal County, OK

Coal County, Oklahoma Zone 7b May

Your May planting checklist for Coal County, Oklahoma

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

Avg. last frost March 28
Avg. first frost November 2
Soil temp (4") 69°F
Watering Low
Pest pressure Moderate
Daylight 13.8 hrs
  1. Fire up the seed-starting tray: eggplant

    Your window is short. These crops want several weeks of indoor growth before they go outside.

A few tasks this May that'll pay off in June
  • 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.

Coal County, Oklahoma is in USDA Zone 7b. The average last spring frost is March 28 and the first fall frost is November 2, giving you a growing season of approximately 219 days.

At an elevation of 892 feet, Coal County receives approximately 28.5 inches of rainfall annually with predominantly loam soil. Summer highs average 89°F, providing good warmth for Eggplant during the growing season.

Coal County, OK (Zone 7b) Long season
219 days
Last Spring Frost March 28
219 growing days
First Fall Frost November 2

Coal County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (74 days to spare)
Start indoors: Jan 17 Transplant: Apr 4 🍅 Harvest: Jun 13 – Aug 15
Recommended (50%) ✓ Fits season (72 days to spare)
Start indoors: Jan 24 Transplant: Apr 11 🍅 Harvest: Jun 20 – Aug 22
Safe Start (90%) ✓ Fits season (74 days to spare)
Start indoors: Feb 12 Transplant: Apr 30 🍅 Harvest: Jul 9 – Sep 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 Coal County

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

Soil pH

Your soil pH (6.5–7.2) overlaps with Eggplant's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.0%) — Eggplant will thrive.

How to Plant Eggplant

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

Succession Planting Eggplant

3
successive plantings in your 219-day season

Sow every 7.4 weeks. Last sowing by Aug 09 to harvest before frost.

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.6″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 1,294 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 0.7" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 4.8" 1.6" 3.2" 🚿 Regular watering
Apr 4.8" 2.7" 2.1" 💧 Light watering
May 4.8" 4.2" 0.6" 💧 Light watering
Jun 4.8" 4.8" 0" ✅ Rainfall sufficient
Jul 4.8" 3.7" 1.1" 💧 Light watering
Aug 4.8" 3.6" 1.2" 💧 Light watering
Sep 4.8" 2.8" 2" 💧 Light watering
Oct 4.8" 1.9" 2.9" 🚿 Regular watering
Nov 4.8" 1" 3.8" 🚿 Regular watering
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Coal 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 ~1,256 GDD — county provides 3,668 GDD Excellent fit

Eggplant Planting Timeline — Coal County, OK

Eggplant Planting Calendar

Activity When Date Range
Start Indoors January 24 Jan 24 – Feb 7
Transplant Outdoors April 11 Apr 11 – Apr 25
Direct Sow April 4 Apr 4 – Apr 25
Harvest June 20 Jun 20 – Aug 22

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors
March
April Transplant Outdoors Direct Sow
May
June Harvest
July Harvest
August Harvest
September
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: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

219 days in Coal County

Growing Tips for Eggplant in Coal County

Direct sow Eggplant outdoors after March 28 in Coal 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 Coal County, OK?

Coal County is in Zone 7b with an average last frost of March 28. Plan your Eggplant planting based on this frost date — see the calendar above for exact timing.

What planting zone is Coal County, OK?

Coal County, Oklahoma is in USDA Hardiness Zone 7b. The average last spring frost is March 28 and first fall frost is November 2.

🌱

Your Coal County Garden Planner — Free

A 24-page printable planner built for Coal County (Zone 7b). 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 Coal County, OK. 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.