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When to Plant Radicchio in Carroll County, IN

Carroll County, Indiana Zone 5b April

What to do in April

We've pulled the most time-sensitive tasks for Carroll County, Indiana this April and put them front and centre. Tackle them in order.

Avg. last frost April 23
Avg. first frost October 16
Soil temp (4") 43°F
Watering Moderate
Pest pressure Low
Daylight 13.1 hrs
  1. Plant out radicchio

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Put radicchio seeds straight in the ground

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

Coming up in May — start thinking about
  • Starting indoors: 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.

Carroll County, Indiana is in USDA Zone 5b. The average last spring frost is April 23 and the first fall frost is October 16, giving you a growing season of approximately 176 days.

At an elevation of 1,252 feet, Carroll County receives approximately 41.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Radicchio to ensure they mature before fall.

Carroll County, IN (Zone 5b) Moderate season
176 days
Last Spring Frost April 23
176 growing days
First Fall Frost October 16
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Carroll County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (78 days to spare)
Start indoors: Mar 14 Transplant: Apr 18 🍅 Harvest: Jun 20 – Jul 25
Recommended (50%) ✓ Fits season (78 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: Jun 25 – Jul 30
Safe Start (90%) ✓ Fits season (78 days to spare)
Start indoors: Apr 2 Transplant: May 7 🍅 Harvest: Jul 9 – Aug 13

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 Carroll County

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

Soil pH

Your soil pH (5.8–6.8) overlaps with Radicchio's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Radicchio.

Organic Matter

Organic matter is excellent (4.1%) — 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 176-day season

Sow every 6.9 weeks. Last sowing by Jul 28 to harvest before frost.

For a dedicated fall crop, sow by Aug 07.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
1.0″/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 1.5" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 3" 3.6" 0" ✅ Rainfall sufficient
May 3" 5.4" 0" ✅ Rainfall sufficient
Jun 3" 5.7" 0" ✅ Rainfall sufficient
Jul 3" 4.4" 0" ✅ Rainfall sufficient
Aug 3" 4.9" 0" ✅ Rainfall sufficient
Sep 3" 3.4" 0" ✅ Rainfall sufficient
Oct 3" 3.2" 0" ✅ Rainfall sufficient
Nov 2.8" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Carroll 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 ~858 GDD — county provides 2,156 GDD Excellent fit

Radicchio Planting Timeline — Carroll County, IN

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 7 Aug 7 – Aug 21

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
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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: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

176 days in Carroll County

Growing Tips for Radicchio in Carroll County

Direct sow Radicchio outdoors after April 23 in Carroll 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 Carroll County, IN?

Carroll County is in Zone 5b with an average last frost of April 23. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.

What planting zone is Carroll County, IN?

Carroll County, Indiana is in USDA Hardiness Zone 5b. The average last spring frost is April 23 and first fall frost is October 16.

🌱

Your Carroll County Garden Planner — Free

A 24-page printable planner built for Carroll 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 Carroll County, IN. Local conditions may vary. Last updated: April 2026.

Sources & credits

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