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When to Plant Watermelon in McCulloch County, TX

McCulloch County, Texas Zone 8b May

Your May gardening checklist

Here's what deserves your attention in McCulloch County, Texas this month. Everything below is tailored to Zone 8b and timed around your local frost dates.

Avg. last frost March 17
Avg. first frost November 16
Soil temp (4") 73°F
Watering Low
Pest pressure High
Daylight 13.6 hrs
To set up a strong June, finish these tasks
  • First harvests: watermelon

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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.

McCulloch County, Texas is in USDA Zone 8b. The average last spring frost is March 17 and the first fall frost is November 16, giving you a growing season of approximately 244 days.

At an elevation of 1,250 feet, McCulloch County receives approximately 60.1 inches of rainfall annually with predominantly loam soil. Summer highs average 96°F, so Watermelon may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Watermelon root diseases.

McCulloch County, TX (Zone 8b) Long season
244 days
Last Spring Frost March 17
244 growing days
First Fall Frost November 16

McCulloch County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (115 days to spare)
Start indoors: Feb 8 Transplant: Mar 22 🍅 Harvest: May 31 – Jul 19
Recommended (50%) ✓ Fits season (111 days to spare)
Start indoors: Feb 17 Transplant: Mar 31 🍅 Harvest: Jun 9 – Jul 28
Safe Start (90%) ✓ Fits season (108 days to spare)
Start indoors: Mar 11 Transplant: Apr 22 🍅 Harvest: Jul 1 – Aug 19

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 McCulloch County

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

Soil pH

Your soil pH (6.8–7.7) overlaps with Watermelon's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is low (1.9%). Add 2-3 inches of compost before planting Watermelon.

How to Plant Watermelon

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

Succession Planting Watermelon

4
successive plantings in your 244-day season

Sow every 8 weeks. Last sowing by Aug 08 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.0″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,213 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 1.8" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 6.5" 3.5" 3" 💧 Light watering
Apr 6.5" 6.6" 0" ✅ Rainfall sufficient
May 6.5" 9.8" 0" ✅ Rainfall sufficient
Jun 6.5" 8.6" 0" ✅ Rainfall sufficient
Jul 6.5" 8" 0" ✅ Rainfall sufficient
Aug 6.5" 7" 0" ✅ Rainfall sufficient
Sep 6.5" 5.1" 1.4" 💧 Light watering
Oct 6.5" 3.9" 2.6" 💧 Light watering
Nov 6.5" 2.2" 4.3" 🚿 Regular watering
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in McCulloch 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 ~1,870 GDD — county provides 5,368 GDD Excellent fit

Watermelon Planting Timeline — McCulloch County, TX

Watermelon Planting Calendar

Activity When Date Range
Start Indoors February 17 Feb 17 – Mar 3
Transplant Outdoors March 31 Mar 31 – Apr 14
Direct Sow March 24 Mar 24 – Apr 14
Harvest June 9 Jun 9 – Jul 28

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · 1-2 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

244 days in McCulloch County

Growing Tips for Watermelon in McCulloch County

Direct sow Watermelon outdoors after March 17 in McCulloch County when soil has warmed and frost danger has passed.

With summer highs reaching 96°F in McCulloch County, provide afternoon shade for Watermelon and water deeply in the morning.

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.

Recommended Watermelon Varieties for McCulloch County

Full-size melons that thrive with your long season

Crimson Sweet (85d) Charleston Gray (85d) Moon and Stars (95d)

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 McCulloch County, TX?

McCulloch County is in Zone 8b with an average last frost of March 17. Plan your Watermelon planting based on this frost date — see the calendar above for exact timing.

What planting zone is McCulloch County, TX?

McCulloch County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 17 and first fall frost is November 16.

🌱

Your McCulloch County Garden Planner — Free

A 24-page printable planner built for McCulloch County (Zone 8b). 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 McCulloch County, TX. 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.