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When to Plant Watermelon Radish in Saint Helens, Oregon (97051)

Location

Saint Helens, Oregon

ZIP Code

97051

USDA Zone

8b

Last Frost

Sunday, March 15, 2026

📅 Planting Calendar

Direct Sow Outdoors Sunday, February 15, 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 Saint Helens?

Get your seeds now so they're ready by Sunday, February 15, 2026.

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🤝 Good Companions

CarrotSpinachLettucePea

⚠️ Avoid Planting Near

Hyssop

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Growing Watermelon Radish in Zone 8b

Watermelon Radish (Raphanus sativus) is a popular garden vegetable. In Saint Helens, Oregon, which is in USDA Hardiness Zone 8b, you should direct sow seeds around Sunday, February 15, 2026.

Your average last frost date is Sunday, March 15, 2026. Watermelon Radish grows well when direct sown, as it doesn't transplant well or germinates quickly outdoors.