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When to plant Radicchio in Mapleton, IL

In Mapleton, plant Radicchio in spring between April 9 and April 30, once soil temps hold above 50°F. Mapleton's last frost averages April 23, so time plantings around the expected last-frost window for best survival. For a fall crop, sow between August 3 and August 17 — roughly 60–80 days before the first frost on October 12.

When to Plant Radicchio in Mapleton, IL

Peoria County, Illinois Zone 6a August

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Avg. last frost April 23
Avg. first frost October 12
Soil temp (4") 78°F
Watering Moderate
Pest pressure High
Daylight 13.6 hrs
  1. Get radicchio in for a late-season harvest

    Your first frost is about 9 weeks away — plenty of time for these to mature.

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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.

Mapleton, Illinois is in USDA Zone 6a. The average last spring frost is April 23 and the first fall frost is October 12, giving you a growing season of approximately 172 days.

At an elevation of 884 feet, Peoria County receives approximately 33 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Radicchio during the growing season.

Mapleton, IL (Zone 6a) Moderate season
172 days
Last Spring Frost April 23
172 growing days
First Fall Frost October 12

Mapleton Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7

Drainage

Well Drained

Radicchio Planting Risk Windows

Early Start (70% safe) ✓ Fits season (76 days to spare)
Start indoors: Mar 13 Transplant: Apr 17 🍅 Harvest: Jun 19 – Jul 24
Recommended (50%) ✓ Fits season (74 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: Jun 25 – Jul 30
Safe Start (90%) ✓ Fits season (75 days to spare)
Start indoors: Apr 3 Transplant: May 8 🍅 Harvest: Jul 10 – Aug 14

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 Mapleton

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

Soil pH

Your soil pH (6.1–7.0) is within Radicchio's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.7%) — Radicchio will thrive.

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

3
successive plantings in your 172-day season

Sow every 6.9 weeks. Last sowing by Jul 24 to harvest before frost.

For a dedicated fall crop, sow by Aug 03.

Radicchio Water Budget

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

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 1.5" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 3" 3.5" 0" ✅ Rainfall sufficient
May 3" 4.2" 0" ✅ Rainfall sufficient
Jun 3" 3.9" 0" ✅ Rainfall sufficient
Jul 3" 3.2" 0" ✅ Rainfall sufficient
Aug 3" 3.4" 0" ✅ Rainfall sufficient
Sep 3" 3.2" 0" ✅ Rainfall sufficient
Oct 3" 2.8" 0.2" 💧 Light watering
Nov 1.9" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Peoria 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 2,494 GDD Excellent fit

Radicchio Planting Timeline — Mapleton, IL

Radicchio Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 – Apr 2
Transplant Outdoors April 23 Apr 23 – May 7
Direct Sow April 9 Apr 9 – Apr 30
Harvest June 25 Jun 25 – Jul 30
Fall Sowing August 3 Aug 3 – Aug 17

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors
June Harvest
July Harvest
August Fall Sowing
September
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: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

172 days in Peoria County

Growing Tips for Radicchio in Mapleton

Direct sow Radicchio outdoors after April 23 in Peoria 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 →

When should I plant Radicchio in Mapleton, IL?

In Mapleton, IL, plant Radicchio after the last frost (around April 23) and before the first frost (around October 12). Best results when soil holds above 50°F.

What growing zone is Mapleton, IL for Radicchio?

Mapleton sits in USDA Zone 6a. Radicchio grows reliably in zones 4a through 10b, so it's a good fit here.

Can Radicchio grow in Mapleton's climate?

Yes — Radicchio grows well in Mapleton's temperate climate. Mapleton averages a 172-day frost-free season, with last frost around April 23 and first frost around October 12.

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Your Peoria County Garden Planner — Free

A 22-page printable planner built for Peoria 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.

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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 Peoria County, IL. Local conditions may vary. Last updated: August 2026.