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When to Plant Radicchio in Worcester County, MA

Worcester County, Massachusetts Zone 6a May

What to do in May

A quick May briefing for Worcester County, Massachusetts gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 24
Avg. first frost October 17
Soil temp (4") 63°F
Watering Moderate
Pest pressure Low
Daylight 14.4 hrs
  1. Begin indoor sowing: radicchio

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

A few tasks this May that'll pay off in 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.

Worcester County, Massachusetts is in USDA Zone 6a. The average last spring frost is April 24 and the first fall frost is October 17, giving you a growing season of approximately 176 days.

At an elevation of 972 feet, Worcester County receives approximately 38 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Radicchio during the growing season.

Worcester County, MA (Zone 6a) Moderate season
176 days
Last Spring Frost April 24
176 growing days
First Fall Frost October 17

Worcester County Soil Profile

Soil Type

Silt Loam

Soil pH

4.8-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (76 days to spare)
Start indoors: Mar 16 Transplant: Apr 20 🍅 Harvest: Jun 22 – Jul 27
Recommended (50%) ✓ Fits season (78 days to spare)
Start indoors: Mar 20 Transplant: Apr 24 🍅 Harvest: Jun 26 – Jul 31
Safe Start (90%) ✓ Fits season (74 days to spare)
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Jul 15 – Aug 19

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 Worcester County

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

Soil pH

Your soil pH (4.8–6.3) is more acidic than Radicchio prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Radicchio.

Organic Matter

Organic matter is moderate (3.7%). 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 176-day season

Sow every 6.9 weeks. Last sowing by Jul 29 to harvest before frost.

For a dedicated fall crop, sow by Aug 08.

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 2.3" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 3.4" 0" ❄️ Dormant
Apr 3" 3.7" 0" ✅ Rainfall sufficient
May 3" 3.5" 0" ✅ Rainfall sufficient
Jun 3" 3" 0" ✅ Rainfall sufficient
Jul 3" 4.1" 0" ✅ Rainfall sufficient
Aug 3" 3.3" 0" ✅ Rainfall sufficient
Sep 3" 3" 0" ✅ Rainfall sufficient
Oct 3" 2.8" 0.2" 💧 Light watering
Nov 3.3" 0" ❄️ Dormant
Dec 2.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Worcester 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 ~962 GDD — county provides 2,420 GDD Excellent fit

Radicchio Planting Timeline — Worcester County, MA

Radicchio Planting Calendar

Activity When Date Range
Start Indoors March 20 Mar 20 – Apr 3
Transplant Outdoors April 24 Apr 24 – May 8
Direct Sow April 10 Apr 10 – May 1
Harvest June 26 Jun 26 – Jul 31
Fall Sowing August 8 Aug 8 – Aug 22

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 Direct Sow
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 6a

📆 Growing Season

176 days in Worcester County

Growing Tips for Radicchio in Worcester County

Direct sow Radicchio outdoors after April 24 in Worcester 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 Worcester County, MA?

Worcester County is in Zone 6a with an average last frost of April 24. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.

What planting zone is Worcester County, MA?

Worcester County, Massachusetts is in USDA Hardiness Zone 6a. The average last spring frost is April 24 and first fall frost is October 17.

🌱

Your Worcester County Garden Planner — Free

A 24-page printable planner built for Worcester 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 Worcester County, MA. 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.