When to Plant Watermelon Radish in Pasadena, California (91105)

Location

Pasadena, California

ZIP Code

91105

USDA Zone

10a

Last Frost

Sunday, January 25, 2026

📅 Planting Calendar

Direct Sow Outdoors Sunday, December 28, 2025

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 Pasadena?

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

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🤝 Good Companions

CarrotSpinachLettucePea

⚠️ Avoid Planting Near

Hyssop

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Growing Watermelon Radish in Zone 10a

Watermelon Radish (Raphanus sativus) is a popular garden vegetable. In Pasadena, California, which is in USDA Hardiness Zone 10a, you should direct sow seeds around Sunday, December 28, 2025.

Your average last frost date is Sunday, January 25, 2026. Watermelon Radish grows well when direct sown, as it doesn't transplant well or germinates quickly outdoors.