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When to Plant Radicchio in Middlesex County, CT

Middlesex County, Connecticut Zone 6b May

Your May game plan for Middlesex County, Connecticut

Your Middlesex County, Connecticut garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost April 18
Avg. first frost October 26
Soil temp (4") 64°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
  1. Time to start radicchio inside

    Your window is short. These crops want several weeks of indoor growth before they go outside.

Get ahead of June
  • First harvests: 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.

Middlesex County, Connecticut is in USDA Zone 6b. The average last spring frost is April 18 and the first fall frost is October 26, giving you a growing season of approximately 191 days.

At an elevation of 248 feet, Middlesex County receives approximately 40.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Radicchio during the growing season.

Middlesex County, CT (Zone 6b) Moderate season
191 days
Last Spring Frost April 18
191 growing days
First Fall Frost October 26

Middlesex County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (92 days to spare)
Start indoors: Mar 7 Transplant: Apr 11 🍅 Harvest: Jun 13 – Jul 18
Recommended (50%) ✓ Fits season (93 days to spare)
Start indoors: Mar 14 Transplant: Apr 18 🍅 Harvest: Jun 20 – Jul 25
Safe Start (90%) ✓ Fits season (85 days to spare)
Start indoors: Apr 1 Transplant: May 6 🍅 Harvest: Jul 8 – Aug 12

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 Middlesex County

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

Soil pH

Your soil pH (5.2–6.2) is more acidic than Radicchio prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.8%). 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

3
successive plantings in your 191-day season

Sow every 6.9 weeks. Last sowing by Aug 07 to harvest before frost.

For a dedicated fall crop, sow by Aug 17.

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

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 3.2" 0" ❄️ Dormant
Feb 3" 0" ❄️ Dormant
Mar 3.7" 0" ❄️ Dormant
Apr 3" 3.6" 0" ✅ Rainfall sufficient
May 3" 3.9" 0" ✅ Rainfall sufficient
Jun 3" 4.3" 0" ✅ Rainfall sufficient
Jul 3" 3.4" 0" ✅ Rainfall sufficient
Aug 3" 3.8" 0" ✅ Rainfall sufficient
Sep 3" 3" 0" ✅ Rainfall sufficient
Oct 3" 3" 0" ✅ Rainfall sufficient
Nov 2.8" 0" ❄️ Dormant
Dec 2.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Middlesex 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 ~1,225 GDD — county provides 3,342 GDD Excellent fit

Radicchio Planting Timeline — Middlesex County, CT

Radicchio Planting Calendar

Activity When Date Range
Start Indoors March 14 Mar 14 – Mar 28
Transplant Outdoors April 18 Apr 18 – May 2
Direct Sow April 4 Apr 4 – Apr 25
Harvest June 20 Jun 20 – Jul 25
Fall Sowing August 17 Aug 17 – Aug 31

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April 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: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

191 days in Middlesex County

Growing Tips for Radicchio in Middlesex County

Direct sow Radicchio outdoors after April 18 in Middlesex 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 Middlesex County, CT?

Middlesex County is in Zone 6b with an average last frost of April 18. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.

What planting zone is Middlesex County, CT?

Middlesex County, Connecticut is in USDA Hardiness Zone 6b. The average last spring frost is April 18 and first fall frost is October 26.

🌱

Your Middlesex County Garden Planner — Free

A 24-page printable planner built for Middlesex County (Zone 6b). 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 Middlesex County, CT. 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.