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When to Plant Watermelon in Atascosa County, TX

Atascosa County, Texas Zone 9a May

What to do in May

We've pulled the most time-sensitive tasks for Atascosa County, Texas this May and put them front and centre. Tackle them in order.

Avg. last frost February 26
Avg. first frost November 29
Soil temp (4") 70°F
Watering Low
Pest pressure High
Daylight 13.4 hrs
  1. Collect watermelon at their peak

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Before June arrives, get these ready
  • 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.

Atascosa County, Texas is in USDA Zone 9a. The average last spring frost is February 26 and the first fall frost is November 29, giving you a growing season of approximately 276 days.

At an elevation of 1,942 feet, Atascosa County receives approximately 51.7 inches of rainfall annually with predominantly loam soil. Summer highs average 91°F, providing good warmth for Watermelon during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Watermelon root diseases.

Atascosa County, TX (Zone 9a) Year-round
276 days
Last Spring Frost February 26
276 growing days
First Fall Frost November 29

Atascosa 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 (158 days to spare)
Start indoors: Jan 16 Transplant: Feb 20 🍅 Harvest: May 1 – Jun 19
Recommended (50%) ✓ Fits season (150 days to spare)
Start indoors: Jan 29 Transplant: Mar 5 🍅 Harvest: May 14 – Jul 2
Safe Start (90%) ✓ Fits season (143 days to spare)
Start indoors: Feb 22 Transplant: Mar 29 🍅 Harvest: Jun 7 – Jul 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 Atascosa 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 Atascosa County is excellent for Watermelon — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Watermelon.

Organic Matter

Organic matter is moderate (2.1%). 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 276-day season

Sow every 8 weeks. Last sowing by Aug 21 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
1.2″/week
Watering frequency 2-3 times/week
Season total 2,875 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 1.5" 0" ❄️ Dormant
Feb 6.5" 1.6" 4.9" 🚿 Regular watering
Mar 6.5" 3.5" 3" 💧 Light watering
Apr 6.5" 4.8" 1.7" 💧 Light watering
May 6.5" 7.6" 0" ✅ Rainfall sufficient
Jun 6.5" 7.4" 0" ✅ Rainfall sufficient
Jul 6.5" 7.4" 0" ✅ Rainfall sufficient
Aug 6.5" 6.6" 0" ✅ Rainfall sufficient
Sep 6.5" 4.9" 1.6" 💧 Light watering
Oct 6.5" 3.1" 3.4" 🚿 Regular watering
Nov 6.5" 2" 4.5" 🚿 Regular watering
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in Atascosa 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 ~1,551 GDD — county provides 5,055 GDD Excellent fit

Watermelon Planting Timeline — Atascosa County, TX

Watermelon Planting Calendar

Activity When Date Range
Start Indoors January 29 Jan 29 – Feb 12
Transplant Outdoors March 5 Mar 5 – Mar 19
Direct Sow February 26 Feb 26 – Mar 19
Harvest May 14 May 14 – Jul 2

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

Month-by-Month Timeline

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

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 9a

📆 Growing Season

276 days in Atascosa County

Growing Tips for Watermelon in Atascosa County

Direct sow Watermelon outdoors after February 26 in Atascosa 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.

Recommended Watermelon Varieties for Atascosa 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 Atascosa County, TX?

Atascosa County is in Zone 9a with an average last frost of February 26. Plan your Watermelon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Atascosa County, TX?

Atascosa County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 26 and first fall frost is November 29.

🌱

Your Atascosa County Garden Planner — Free

A 24-page printable planner built for Atascosa County (Zone 9a). 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 Atascosa 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.