When to Plant Radicchio in Pitkin County, CO
Radicchio is an Italian chicory with stunning red and white leaves and a pleasantly bitter flavor. It forms tight heads and is used in salads, grilled, or braised.
Pitkin County, Colorado is in USDA Zone 4a. The average last spring frost is June 16 and the first fall frost is September 7, giving you a growing season of approximately 83 days.
At an elevation of 6,411 feet, Pitkin County receives approximately 17.8 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Radicchio to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Radicchio successfully. Mulch heavily to conserve soil moisture.
Pitkin County Soil Profile
Soil Type
Loam
Soil pH
6.6-8.3
Drainage
Well Drained
Plant Planting Risk Windows
Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.
Soil Compatibility in Pitkin County
How your county's soil matches Radicchio's growing requirements.
Soil pH
Your soil pH (6.6–8.3) is more alkaline than Radicchio prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Pitkin County is excellent for Radicchio — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.2%). Annual compost additions will help Radicchio.
How to Plant Radicchio
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Radicchio
Radicchio needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.
| Month | Radicchio Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1" | 0" | ❄️ Dormant |
| Mar | — | 1.7" | 0" | ❄️ Dormant |
| Apr | — | 1.9" | 0" | ❄️ Dormant |
| May | — | 2" | 0" | ❄️ Dormant |
| Jun | 3" | 1.3" | 1.7" | 🚿 Regular watering |
| Jul | 3" | 1.4" | 1.6" | 🚿 Regular watering |
| Aug | 3" | 1.9" | 1.1" | 💧 Light watering |
| Sep | 3" | 1.7" | 1.3" | 💧 Light watering |
| Oct | — | 1.5" | 0" | ❄️ Dormant |
| Nov | — | 1.1" | 0" | ❄️ Dormant |
| Dec | — | 0.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Sep in Pitkin County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Radicchio Heat Requirements (GDD)
What are Growing Degree Days (GDD)?
Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.
Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.
Radicchio Planting Timeline — Pitkin County, CO
Radicchio Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | May 5 | May 5 – May 19 |
| Transplant Outdoors | June 16 | Jun 16 – Jun 30 |
| Direct Sow | June 9 | Jun 9 – Jun 30 |
| Harvest | August 18 | Aug 18 – Sep 22 |
| Fall Sowing | June 15 | Jun 15 – Jun 29 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Start Indoors |
| June | Transplant Outdoors Direct Sow Fall Sowing |
| July | — |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.7"/week · Natural rainfall sufficient
📅 Days to Maturity
60–80 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 4a
📆 Growing Season
83 days in Pitkin County
Growing Tips for Radicchio in Pitkin County
Direct sow Radicchio outdoors after June 16 in Pitkin County when soil has warmed and frost danger has passed.
Your 83.0-day growing season in Pitkin County is tight for Radicchio (60.0-80.0 days to maturity). Start indoors and choose early-maturing varieties.
Common pests for Radicchio in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
General growing tips
Start in late summer for fall harvest. The red color develops with cool nights and light frost. Harvest when heads are firm and compact.
Companion Planting
Good Companions
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Radicchio in Other Locations
Frequently Asked Questions
When should I plant Radicchio in Pitkin County, CO?
Pitkin County is in Zone 4a with an average last frost of June 16. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.
What planting zone is Pitkin County, CO?
Pitkin County, Colorado is in USDA Hardiness Zone 4a. The average last spring frost is June 16 and first fall frost is September 7.
Plan Your Garden with Confidence
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