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When to Plant Watermelon in Irion County, TX

Watermelon
Irion County, Texas Zone 8a July

What to do in July

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

Avg. last frost April 1
Avg. first frost November 7
Soil temp (4") 84°F
Watering Low
Pest pressure High
Daylight 13.8 hrs
  1. Start harvesting watermelon

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

A few tasks this July that'll pay off in August
  • 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.

Irion County, Texas is in USDA Zone 8a. The average last spring frost is April 1 and the first fall frost is November 7, giving you a growing season of approximately 220 days.

At an elevation of 1,818 feet, Irion County receives approximately 51.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 100°F, so Watermelon may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Watermelon will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Watermelon root diseases.

Irion County, TX (Zone 8a) Long season
220 days
Last Spring Frost April 1
220 growing days
First Fall Frost November 7

Irion County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.6-8.6

Drainage

Well Drained

Watermelon Planting Risk Windows

Early Start (70% safe) ✓ Fits season (88 days to spare)
Start indoors: Feb 21 Transplant: Apr 4 🍅 Harvest: Jun 13 – Aug 1
Recommended (50%) ✓ Fits season (87 days to spare)
Start indoors: Mar 4 Transplant: Apr 15 🍅 Harvest: Jun 24 – Aug 12
Safe Start (90%) ✓ Fits season (89 days to spare)
Start indoors: Mar 18 Transplant: Apr 29 🍅 Harvest: Jul 8 – Aug 26

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 Irion County

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

Soil pH

Your soil pH (7.6–8.6) is more alkaline than Watermelon prefers (6.0–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Irion County warms quickly in spring but drains fast. Watermelon will need more frequent watering and regular compost additions to retain nutrients.

Organic Matter

Organic matter is low (1.0%). 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

3
successive plantings in your 220-day season

Sow every 8 weeks. Last sowing by Jul 30 to harvest before frost.

Watermelon 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 1,219 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 3.8" 0" ❄️ Dormant
Feb 3.1" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 6.5" 1.8" 4.7" 🚿 Regular watering
May 6.5" 1.4" 5.1" 🚿 Regular watering
Jun 6.5" 1.7" 4.8" 🚿 Regular watering
Jul 6.5" 9.5" 0" ✅ Rainfall sufficient
Aug 6.5" 9.5" 0" ✅ Rainfall sufficient
Sep 6.5" 6.8" 0" ✅ Rainfall sufficient
Oct 6.5" 4.5" 2" 💧 Light watering
Nov 6.5" 2.8" 3.7" 🚿 Regular watering
Dec 3.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Irion 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 ~2,125 GDD — county provides 5,500 GDD Excellent fit

Watermelon Planting Timeline — Irion County, TX

Watermelon Planting Calendar

Activity When Date Range
Start Indoors March 4 Mar 4 – Mar 18
Transplant Outdoors April 15 Apr 15 – Apr 29
Direct Sow April 8 Apr 8 – Apr 29
Harvest June 24 Jun 24 – Aug 12

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
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

1.5"/week · 1-2 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 8a

📆 Growing Season

220 days in Irion County

Growing Tips for Watermelon in Irion County

Direct sow Watermelon outdoors after April 01 in Irion County when soil has warmed and frost danger has passed.

Sandy soil in Irion County dries quickly — mulch Watermelon with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 100°F in Irion 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 Irion 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 Irion County, TX?

Irion County is in Zone 8a with an average last frost of April 1. Plan your Watermelon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Irion County, TX?

Irion County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is April 1 and first fall frost is November 7.

🌱

Your Irion County Garden Planner — Free

A 22-page printable planner built for Irion County (Zone 8a). 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 Irion County, TX. Local conditions may vary. Last updated: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.