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When to Plant Watermelon in Gallia County, OH

Gallia County, Ohio Zone 6b May

May in Gallia County, Ohio — your action list

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

Avg. last frost April 23
Avg. first frost October 21
Soil temp (4") 63°F
Watering Low
Pest pressure Low
Daylight 14.1 hrs
  1. Get watermelon in the ground

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

  2. Sow watermelon in trays indoors

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

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Watermelon is a sprawling vine crop that produces sweet, juicy fruits in hot weather. Varieties range from personal-sized icebox types to 50-pound giants.

Gallia County, Ohio is in USDA Zone 6b. The average last spring frost is April 23 and the first fall frost is October 21, giving you a growing season of approximately 181 days.

At an elevation of 599 feet, Gallia County receives approximately 33.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Watermelon during the growing season.

Gallia County, OH (Zone 6b) Moderate season
181 days
Last Spring Frost April 23
181 growing days
First Fall Frost October 21
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Gallia County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (53 days to spare)
Start indoors: Mar 10 Transplant: Apr 28 🍅 Harvest: Jul 7 – Aug 25
Recommended (50%) ✓ Fits season (48 days to spare)
Start indoors: Mar 19 Transplant: May 7 🍅 Harvest: Jul 16 – Sep 3
Safe Start (90%) ✓ Fits season (43 days to spare)
Start indoors: Apr 5 Transplant: May 24 🍅 Harvest: Aug 2 – Sep 20

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 Gallia County

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

Soil pH

Your soil pH (5.9–7.3) overlaps with Watermelon's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.0%) — Watermelon will thrive.

How to Plant Watermelon

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

Succession Planting Watermelon

2
successive plantings in your 181-day season

Sow every 8 weeks. Last sowing by Jul 13 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,388 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Watermelon

Watermelon needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Watermelon Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 6.5" 3.3" 3.2" 💧 Light watering
May 6.5" 3.8" 2.7" 💧 Light watering
Jun 6.5" 4.2" 2.3" 💧 Light watering
Jul 6.5" 4.2" 2.3" 💧 Light watering
Aug 6.5" 3.4" 3.1" 💧 Light watering
Sep 6.5" 2.9" 3.6" 🚿 Regular watering
Oct 6.5" 2.6" 3.9" 🚿 Regular watering
Nov 2" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Gallia County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Watermelon 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.

Watermelon needs ~1,232 GDD — county provides 2,624 GDD Excellent fit

Watermelon Planting Timeline — Gallia County, OH

Watermelon Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 – Apr 2
Transplant Outdoors May 7 May 7 – May 21
Direct Sow April 30 Apr 30 – May 21
Harvest July 16 Jul 16 – Sep 3

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

181 days in Gallia County

Growing Tips for Watermelon in Gallia County

Direct sow Watermelon outdoors after April 23 in Gallia County when soil has warmed and frost danger has passed.

Common pests for Watermelon in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 3-4 weeks early or direct sow after soil is warm. Plant on mounds with plenty of space. Check ripeness by looking for a yellow ground spot and dull thump when tapped.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Watermelon in Gallia County, OH?

Gallia County is in Zone 6b with an average last frost of April 23. Plan your Watermelon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Gallia County, OH?

Gallia County, Ohio is in USDA Hardiness Zone 6b. The average last spring frost is April 23 and first fall frost is October 21.

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Your Gallia County Garden Planner — Free

A 24-page printable planner built for Gallia County (Zone 6b). 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 Gallia 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.