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When to Plant Radicchio in Chaffee County, CO

Chaffee County, Colorado Zone 5b May

Your May gardening checklist

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Chaffee County, Colorado.

Avg. last frost June 16
Avg. first frost September 7
Soil temp (4") 37°F
Watering High
Pest pressure Low
Daylight 14.1 hrs
Before June arrives, get these ready
  • Transplants going out: radicchio
  • Direct-sowing: radicchio
  • Fall sowing: radicchio

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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.

Chaffee County, Colorado is in USDA Zone 5b. 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 7,788 feet, Chaffee County receives approximately 18.6 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Radicchio during the growing season. With low rainfall, drip irrigation is essential for growing Radicchio successfully. Mulch heavily to conserve soil moisture.

Chaffee County, CO (Zone 5b) Very short season
83 days
Last Spring Frost June 16
83 growing days
First Fall Frost September 7
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Chaffee County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: May 6 Transplant: Jun 10 🍅 Harvest: Aug 12 – Sep 16
Recommended (50%) ✗ May not fit
Start indoors: May 12 Transplant: Jun 16 🍅 Harvest: Aug 18 – Sep 22
Safe Start (90%) ✗ May not fit
Start indoors: May 22 Transplant: Jun 26 🍅 Harvest: Aug 28 – Oct 2

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 Chaffee County

How your county's soil matches Radicchio's growing requirements.

Soil pH

Your soil pH (6.7–7.6) is more alkaline than Radicchio prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Chaffee County is excellent for Radicchio — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Radicchio.

How to Plant Radicchio

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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 1.4" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.4" 0" ❄️ Dormant
Apr 1.8" 0" ❄️ Dormant
May 2.4" 0" ❄️ Dormant
Jun 3" 1.4" 1.6" 🚿 Regular watering
Jul 3" 1.8" 1.2" 💧 Light watering
Aug 3" 1.9" 1.1" 💧 Light watering
Sep 3" 1.4" 1.6" 🚿 Regular watering
Oct 1.5" 0" ❄️ Dormant
Nov 1.3" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Chaffee 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 needs ~1,015 GDD — county provides 1,203 GDD Good fit

Radicchio Planting Timeline — Chaffee County, CO

Radicchio Planting Calendar

Activity When Date Range
Start Indoors May 12 May 12 – May 26
Transplant Outdoors June 16 Jun 16 – Jun 30
Direct Sow June 2 Jun 2 – Jun 23
Harvest August 18 Aug 18 – Sep 22
Fall Sowing June 29 Jun 29 – Jul 13

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Start Indoors
June Transplant Outdoors Direct Sow Fall Sowing
July Fall Sowing
August Harvest
September Harvest
October
November
December
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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 5b

📆 Growing Season

83 days in Chaffee County

Growing Tips for Radicchio in Chaffee County

Direct sow Radicchio outdoors after June 16 in Chaffee County when soil has warmed and frost danger has passed.

Your 83.0-day growing season in Chaffee 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

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Radicchio in Chaffee County, CO?

Chaffee County is in Zone 5b 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 Chaffee County, CO?

Chaffee County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is June 16 and first fall frost is September 7.

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Your Chaffee County Garden Planner — Free

A 24-page printable planner built for Chaffee County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Chaffee County, CO. Local conditions may vary. Last updated: May 2026.

Sources & credits

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