When to Plant Radicchio in Boulder, Colorado (80310)

Location

Boulder, Colorado

ZIP Code

80310

USDA Zone

Last Frost

Monday, April 20, 2026

📅 Planting Calendar

Start Seeds Indoors Monday, March 23, 2026

Transplant Outdoors Monday, April 6, 2026

Pro Tip: Start Radicchio seeds indoors 4 weeks before your last frost date, then transplant outdoors around Monday, April 6, 2026.

🌿 Plant Details

Scientific Name Cichorium intybus

Days to Maturity 80 days

Mature Height 6-12"

Spread 10"

Type Head

Fruit Size Small-Medium (fist-sized head)

☀️ Growing Requirements

☀️

Sun

Full Sun to Partial Shade

💧

Water

Regular (keep moist)

↔️

Spacing

10" apart

🌱

Planting Depth

0.25" deep

Seeds typically germinate in 5-10 days

Ready to Plant Radicchio in Boulder?

Get your seeds now so they're ready by Monday, March 23, 2026.

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Growing Radicchio in Zone 6a

Radicchio (Cichorium intybus) is a popular garden vegetable. In Boulder, Colorado, which is in USDA Hardiness Zone 6a, you should start seeds indoors around Monday, March 23, 2026.

Your average last frost date is Monday, April 20, 2026. Plan to transplant your Radicchio seedlings outdoors around Monday, April 6, 2026, about -2 weeks after your last frost date.