When to Plant Watermelon Radish in Houston, Texas (77021)

Location

Houston, Texas

ZIP Code

77021

USDA Zone

Last Frost

Tuesday, February 10, 2026

📅 Planting Calendar

Direct Sow Outdoors Tuesday, January 13, 2026

Pro Tip: Sow Watermelon Radish directly outdoors 4 weeks before your last frost date.

🌿 Plant Details

Scientific Name Raphanus sativus

Days to Maturity 60 days

Mature Height 6-10"

Spread 4"

☀️ Growing Requirements

☀️

Sun

Full Sun (6-8 hours)

💧

Water

Regular (1-2 inches/week)

↔️

Spacing

4" apart

🌱

Planting Depth

0.5" deep

Seeds typically germinate in 3-7 days

Ready to Plant Watermelon Radish in Houston?

Get your seeds now so they're ready by Tuesday, January 13, 2026.

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🤝 Good Companions

CarrotSpinachLettucePea

⚠️ Avoid Planting Near

Hyssop

Other Plants for Houston

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Growing Watermelon Radish in Zone 9b

Watermelon Radish (Raphanus sativus) is a popular garden vegetable. In Houston, Texas, which is in USDA Hardiness Zone 9b, you should direct sow seeds around Tuesday, January 13, 2026.

Your average last frost date is Tuesday, February 10, 2026. Watermelon Radish grows well when direct sown, as it doesn't transplant well or germinates quickly outdoors.