When to Plant Watermelon in Brownsville, Texas (78521)

Location

Brownsville, Texas

ZIP Code

78521

USDA Zone

10a

Last Frost

Sunday, January 25, 2026

📅 Planting Calendar

Start Seeds Indoors Sunday, December 28, 2025

Transplant Outdoors Sunday, February 8, 2026

Pro Tip: Start Watermelon seeds indoors 4 weeks before your last frost date, then transplant outdoors around Sunday, February 8, 2026.

🌿 Plant Details

Scientific Name Citrullus lanatus

Days to Maturity 80 days

Mature Height 12-24"

Spread 72"

Type Vine

Fruit Size Large (10-30 lbs)

☀️ Growing Requirements

☀️

Sun

Full Sun (8+ hours)

💧

Water

Regular (1-2 inches/week)

↔️

Spacing

72" apart

🌱

Planting Depth

1" deep

Seeds typically germinate in 4-12 days

Ready to Plant Watermelon in Brownsville?

Get your seeds now so they're ready by Sunday, December 28, 2025.

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🤝 Good Companions

CornSunflowerMarigold

⚠️ Avoid Planting Near

Potato

Other Plants for Brownsville

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Growing Watermelon in Zone 10a

Watermelon (Citrullus lanatus) is a popular garden vegetable. In Brownsville, Texas, which is in USDA Hardiness Zone 10a, you should start seeds indoors around Sunday, December 28, 2025.

Your average last frost date is Sunday, January 25, 2026. Plan to transplant your Watermelon seedlings outdoors around Sunday, February 8, 2026, about 2 weeks after your last frost date.