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When to Plant Watermelon in San Augustine County, TX

Watermelon

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.

San Augustine County, Texas is in USDA Zone 9a. The average last spring frost is March 5 and the first fall frost is November 16, giving you a growing season of approximately 256 days.

At an elevation of 146 feet, San Augustine County receives approximately 62.7 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96°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.

San Augustine County, TX (Zone 9a) Long season
256 days
Last Spring Frost March 5
256 growing days
First Fall Frost November 16

San Augustine County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.4-6.6

Drainage

Well Drained

How Much Watermelon to Grow

15-20 lbs
Average yield per plant
1
Plants per person
2 sq ft
Space per person

For a family of 4, plant approximately 4 watermelon plants in about 8 sq ft. In San Augustine County's 256-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Monthly Watering Guide for Watermelon

Watermelon needs approximately 1 inches of water per week (4.3" 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 1.9" 0" ❄️ Dormant
Mar 4.3" 3.6" 0.7" 💧 Light watering
Apr 4.3" 6.2" 0" ✅ Rainfall sufficient
May 4.3" 8.2" 0" ✅ Rainfall sufficient
Jun 4.3" 10.7" 0" ✅ Rainfall sufficient
Jul 4.3" 8.7" 0" ✅ Rainfall sufficient
Aug 4.3" 8.2" 0" ✅ Rainfall sufficient
Sep 4.3" 5.8" 0" ✅ Rainfall sufficient
Oct 4.3" 4.2" 0.1" 💧 Light watering
Nov 4.3" 2.3" 2" 💧 Light watering
Dec 1.5" 0" ❄️ Dormant

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

Watermelon Planting Timeline — San Augustine County, TX

Watermelon Planting Calendar

Activity When Date Range
Start Indoors February 5 Feb 5 – Feb 19
Transplant Outdoors March 12 Mar 12 – Mar 26
Direct Sow March 5 Mar 5 – Mar 26
Harvest May 21 May 21 – Jul 9

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
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

Moderate — regular watering

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: N/A

🗺️ USDA Zone

Zone 9a

📆 Growing Season

256 days in San Augustine County

Growing Tips for San Augustine County

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 San Augustine County, TX?

San Augustine County is in Zone 9a with an average last frost of March 5. Plan your Watermelon planting based on this frost date — see the calendar above for exact timing.

What planting zone is San Augustine County, TX?

San Augustine County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is March 5 and first fall frost is November 16.

🌱

Your San Augustine County Garden Planner — Free

A 22-page printable planner built for San Augustine 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.

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 San Augustine 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.