Blog

When to Plant Radicchio in El Paso County, CO

El Paso County, Colorado Zone 6a May

May in El Paso County, Colorado — your action list

Each item below is timed to El Paso County, Colorado's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 11
Avg. first frost October 6
Soil temp (4") 33°F
Watering Moderate
Pest pressure Low
Daylight 14.1 hrs
  1. Time to transplant radicchio

    Your last frost (May 11) has passed. These warm-season crops can handle outdoor soil now.

To set up a strong June, finish these tasks
  • Starting indoors: radicchio

Instant PDF download. No spam, unsubscribe any time.

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.

El Paso County, Colorado is in USDA Zone 6a. The average last spring frost is May 11 and the first fall frost is October 6, giving you a growing season of approximately 148 days.

At an elevation of 8,317 feet, El Paso County receives approximately 23.5 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Radicchio during the growing season.

El Paso County, CO (Zone 6a) Short season
148 days
Last Spring Frost May 11
148 growing days
First Fall Frost October 6

El Paso County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (48 days to spare)
Start indoors: Mar 30 Transplant: May 4 🍅 Harvest: Jul 6 – Aug 10
Recommended (50%) ✓ Fits season (50 days to spare)
Start indoors: Apr 6 Transplant: May 11 🍅 Harvest: Jul 13 – Aug 17
Safe Start (90%) ✓ Fits season (45 days to spare)
Start indoors: Apr 22 Transplant: May 27 🍅 Harvest: Jul 29 – Sep 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 El Paso County

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

Soil pH

Your soil pH (6.5–7.9) is more alkaline than Radicchio prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). 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.

Succession Planting Radicchio

2
successive plantings in your 148-day season

Sow every 6.9 weeks. Last sowing by Jul 18 to harvest before frost.

For a dedicated fall crop, sow by Jul 28.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.7″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 52 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 1.7" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 3" 2.8" 0.2" 💧 Light watering
Jun 3" 1.6" 1.4" 💧 Light watering
Jul 3" 2.3" 0.7" 💧 Light watering
Aug 3" 3" 0" ✅ Rainfall sufficient
Sep 3" 1.7" 1.3" 💧 Light watering
Oct 3" 1.9" 1.1" 💧 Light watering
Nov 1.5" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in El Paso 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 ~1,068 GDD — county provides 2,257 GDD Excellent fit

Radicchio Planting Timeline — El Paso County, CO

Radicchio Planting Calendar

Activity When Date Range
Start Indoors April 6 Apr 6 – Apr 20
Transplant Outdoors May 11 May 11 – May 25
Direct Sow April 27 Apr 27 – May 18
Harvest July 13 Jul 13 – Aug 17
Fall Sowing July 28 Jul 28 – Aug 11

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · Only during dry spells

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

148 days in El Paso County

Growing Tips for Radicchio in El Paso County

Direct sow Radicchio outdoors after May 11 in El Paso County when soil has warmed and frost danger has passed.

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 El Paso County, CO?

El Paso County is in Zone 6a with an average last frost of May 11. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.

What planting zone is El Paso County, CO?

El Paso County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is May 11 and first fall frost is October 6.

🌱

Your El Paso County Garden Planner — Free

A 24-page printable planner built for El Paso County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

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

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.