Blog

When to Plant Watermelon in Tarrant County, TX

Tarrant County, Texas Zone 8b May

May in Tarrant County, Texas — your action list

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 18
Avg. first frost November 12
Soil temp (4") 65°F
Watering Low
Pest pressure High
Daylight 13.7 hrs
A few tasks this May that'll pay off in June
  • First harvests: watermelon

Instant PDF download. No spam, unsubscribe any time.

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.

Tarrant County, Texas is in USDA Zone 8b. The average last spring frost is March 18 and the first fall frost is November 12, giving you a growing season of approximately 239 days.

At an elevation of 3,487 feet, Tarrant County receives approximately 63.1 inches of rainfall annually with predominantly clay soil. Summer highs average 92°F, providing good warmth for Watermelon during the growing season. Clay soil retains moisture well for Watermelon, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Watermelon root diseases.

Tarrant County, TX (Zone 8b) Long season
239 days
Last Spring Frost March 18
239 growing days
First Fall Frost November 12
Share this guide:

Tarrant County Soil Profile

Soil Type

Clay

Soil pH

7.3-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (114 days to spare)
Start indoors: Feb 6 Transplant: Mar 20 🍅 Harvest: May 29 – Jul 17
Recommended (50%) ✓ Fits season (106 days to spare)
Start indoors: Feb 18 Transplant: Apr 1 🍅 Harvest: Jun 10 – Jul 29
Safe Start (90%) ✓ Fits season (103 days to spare)
Start indoors: Mar 15 Transplant: Apr 26 🍅 Harvest: Jul 5 – Aug 23

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 Tarrant County

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

Soil pH

Your soil pH (7.3–8.1) is more alkaline than Watermelon prefers (6.0–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

Heavy clay soil (45% clay) in Tarrant County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.

Organic Matter

Organic matter is moderate (3.1%). Annual compost additions will help Watermelon.

How to Plant Watermelon

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

Succession Planting Watermelon

4
successive plantings in your 239-day season

Sow every 8 weeks. Last sowing by Aug 04 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.1″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 832 gal / 100 sq ft

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 2.2" 0" ❄️ Dormant
Mar 6.5" 3.8" 2.7" 💧 Light watering
Apr 6.5" 7" 0" ✅ Rainfall sufficient
May 6.5" 9.8" 0" ✅ Rainfall sufficient
Jun 6.5" 10.1" 0" ✅ Rainfall sufficient
Jul 6.5" 7.2" 0" ✅ Rainfall sufficient
Aug 6.5" 8.1" 0" ✅ Rainfall sufficient
Sep 6.5" 5.5" 1" 💧 Light watering
Oct 6.5" 4.1" 2.4" 💧 Light watering
Nov 6.5" 2.2" 4.3" 🚿 Regular watering
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Tarrant 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 ~1,615 GDD — county provides 4,541 GDD Excellent fit

Watermelon Planting Timeline — Tarrant County, TX

Watermelon Planting Calendar

Activity When Date Range
Start Indoors February 18 Feb 18 – Mar 4
Transplant Outdoors April 1 Apr 1 – Apr 15
Direct Sow March 25 Mar 25 – Apr 15
Harvest June 10 Jun 10 – Jul 29

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

Month-by-Month Timeline

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

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: too_alkaline

🗺️ USDA Zone

Zone 8b

📆 Growing Season

239 days in Tarrant County

Growing Tips for Watermelon in Tarrant County

Direct sow Watermelon outdoors after March 18 in Tarrant County when soil has warmed and frost danger has passed.

With Tarrant County's clay soil (45% clay), work in 3-4 inches of compost before planting Watermelon. Avoid tilling when soil is wet to prevent compaction.

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 Tarrant 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 Tarrant County, TX?

Tarrant County is in Zone 8b with an average last frost of March 18. Plan your Watermelon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Tarrant County, TX?

Tarrant County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 18 and first fall frost is November 12.

🌱

Your Tarrant County Garden Planner — Free

A 24-page printable planner built for Tarrant 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.

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 Tarrant 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.