Blog

When to plant Radicchio in Piatt County, IL

The best window to plant Radicchio in Piatt County, is March 31–April 21, when soil warms to 50°F. Last frost typically hits April 14; first frost October 16. A second sowing from August 7 to August 21 extends the harvest into fall.

When to Plant Radicchio in Piatt County, IL

Piatt County, Illinois Zone 6a July

July in the garden — Piatt County, Illinois

If you only do a handful of things in the garden this July, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 14
Avg. first frost October 16
Soil temp (4") 77°F
Watering Low
Pest pressure High
Daylight 14.6 hrs
  1. Pick radicchio

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

To set up a strong August, finish these tasks
  • Fall sowing: 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.

Piatt County, Illinois is in USDA Zone 6a. The average last spring frost is April 14 and the first fall frost is October 16, giving you a growing season of approximately 185 days.

At an elevation of 1,118 feet, Piatt County receives approximately 38.8 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.

Piatt County, IL (Zone 6a) Moderate season
185 days
Last Spring Frost April 14
185 growing days
First Fall Frost October 16

Piatt County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.1

Drainage

Well Drained

Radicchio Planting Risk Windows

Early Start (70% safe) ✓ Fits season (87 days to spare)
Start indoors: Mar 5 Transplant: Apr 9 🍅 Harvest: Jun 11 – Jul 16
Recommended (50%) ✓ Fits season (87 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: Jun 16 – Jul 21
Safe Start (90%) ✓ Fits season (93 days to spare)
Start indoors: Mar 20 Transplant: Apr 24 🍅 Harvest: Jun 26 – Jul 31

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 Piatt County

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

Soil pH

Your soil pH (6.0–7.1) overlaps with Radicchio's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.0%) — 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 185-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.

Radicchio 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 1.6" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 3" 4.2" 0" ✅ Rainfall sufficient
May 3" 4.7" 0" ✅ Rainfall sufficient
Jun 3" 4.6" 0" ✅ Rainfall sufficient
Jul 3" 4.5" 0" ✅ Rainfall sufficient
Aug 3" 3.7" 0" ✅ Rainfall sufficient
Sep 3" 3.3" 0" ✅ Rainfall sufficient
Oct 3" 2.7" 0.3" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Piatt 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 2,266 GDD Excellent fit

Radicchio Planting Timeline — Piatt County, IL

Radicchio Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 – Mar 24
Transplant Outdoors April 14 Apr 14 – Apr 28
Direct Sow March 31 Mar 31 – Apr 21
Harvest June 16 Jun 16 – Jul 21
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 Direct Sow
April Transplant Outdoors Direct Sow
May
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: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

185 days in Piatt County

Growing Tips for Radicchio in Piatt County

Direct sow Radicchio outdoors after April 14 in Piatt 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 Piatt County, IL?

Piatt County is in Zone 6a with an average last frost of April 14. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.

What planting zone is Piatt County, IL?

Piatt County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 14 and first fall frost is October 16.

When should I plant Radicchio in Piatt County, IL?

In Piatt County, IL, plant Radicchio after the last frost (around April 14) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is Piatt County, IL for Radicchio?

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

Can Radicchio grow in Piatt County's climate?

Yes — Radicchio grows well in Piatt County's temperate climate. Piatt County averages a 185-day frost-free season, with last frost around April 14 and first frost around October 16.

🌱

Your Piatt County Garden Planner — Free

A 22-page printable planner built for Piatt 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 Piatt County, IL. Local conditions may vary. Last updated: July 2026.

Sources & credits

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