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When to Plant Watermelon in Austin County, TX

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.

Austin County, Texas is in USDA Zone 8b. The average last spring frost is February 28 and the first fall frost is November 29, giving you a growing season of approximately 274 days.

At an elevation of 350 feet, Austin County receives approximately 68.9 inches of rainfall annually with predominantly clay soil. Summer highs average 90ยฐF, 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.

Austin County, TX (Zone 8b) Year-round
274 days
Last Spring Frost February 28
274 growing days
First Fall Frost November 29

Austin County Soil Profile

Soil Type

Clay

Soil pH

6.8-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (142 days to spare)
Start indoors: Jan 16 Transplant: Feb 27 🍅 Harvest: May 8 – Jun 26
Recommended (50%) ✓ Fits season (141 days to spare)
Start indoors: Jan 31 Transplant: Mar 14 🍅 Harvest: May 23 – Jul 11
Safe Start (90%) ✓ Fits season (141 days to spare)
Start indoors: Feb 22 Transplant: Apr 5 🍅 Harvest: Jun 14 – Aug 2

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 Austin County

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

Soil pH

Your soil pH (6.8โ€“8.1) overlaps with Watermelon's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

Heavy clay soil (41% clay) in Austin County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.

Organic Matter

Organic matter is moderate (3.2%). 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 274-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
1.1″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 1,315 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” 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 โ€” 1.7" 0" โ„๏ธ Dormant
Feb 6.5" 2.4" 4.1" ๐Ÿšฟ Regular watering
Mar 6.5" 4.3" 2.2" ๐Ÿ’ง Light watering
Apr 6.5" 7.2" 0" โœ… Rainfall sufficient
May 6.5" 9.6" 0" โœ… Rainfall sufficient
Jun 6.5" 11.9" 0" โœ… Rainfall sufficient
Jul 6.5" 8.5" 0" โœ… Rainfall sufficient
Aug 6.5" 9.2" 0" โœ… Rainfall sufficient
Sep 6.5" 5.7" 0.8" ๐Ÿ’ง Light watering
Oct 6.5" 4.6" 1.9" ๐Ÿ’ง Light watering
Nov 6.5" 2.2" 4.3" ๐Ÿšฟ Regular watering
Dec โ€” 1.8" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Febโ€“Nov in Austin County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~1,488 GDD — county provides 4,812 GDD Excellent fit

Watermelon Planting Timeline โ€” Austin County, TX

Watermelon Planting Calendar

Activity When Date Range
Start Indoors January 31 Jan 31 โ€“ Feb 14
Transplant Outdoors March 14 Mar 14 โ€“ Mar 28
Direct Sow March 7 Mar 7 โ€“ Mar 28
Harvest May 23 May 23 โ€“ Jul 11

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.5"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

70โ€“100 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 8b

๐Ÿ“† Growing Season

274 days in Austin County

Growing Tips for Watermelon in Austin County

Direct sow Watermelon outdoors after February 28 in Austin County when soil has warmed and frost danger has passed.

With Austin County's clay soil (41% 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 Austin 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 Austin County, TX?

Austin County is in Zone 8b with an average last frost of February 28. Plan your Watermelon planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Austin County, TX?

Austin County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is February 28 and first fall frost is November 29.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Austin County gardeners in Zone 8b organize planting dates, track what's growing, and never miss a planting window.

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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 Austin County, TX. Local conditions may vary. Last updated: April 2026.