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When to Plant Radicchio in Newport County, RI

Newport County, Rhode Island Zone 7a May

This month in Newport County, Rhode Island

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Newport County, Rhode Island.

Avg. last frost April 30
Avg. first frost October 13
Soil temp (4") 68°F
Watering Low
Pest pressure Moderate
Daylight 14.3 hrs
A few tasks this May that'll pay off in June
  • 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.

Newport County, Rhode Island is in USDA Zone 7a. The average last spring frost is April 30 and the first fall frost is October 13, giving you a growing season of approximately 166 days.

At an elevation of 441 feet, Newport County receives approximately 41.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 94°F, providing good warmth for Radicchio during the growing season.

Newport County, RI (Zone 7a) Moderate season
166 days
Last Spring Frost April 30
166 growing days
First Fall Frost October 13

Newport County Soil Profile

Soil Type

Silt Loam

Soil pH

4.8-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (69 days to spare)
Start indoors: Mar 20 Transplant: Apr 24 🍅 Harvest: Jun 26 – Jul 31
Recommended (50%) ✓ Fits season (68 days to spare)
Start indoors: Mar 26 Transplant: Apr 30 🍅 Harvest: Jul 2 – Aug 6
Safe Start (90%) ✓ Fits season (71 days to spare)
Start indoors: Apr 10 Transplant: May 15 🍅 Harvest: Jul 17 – Aug 21

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 Newport County

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

Soil pH

Your soil pH (4.8–6.7) is more acidic than Radicchio prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Newport 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 166-day season

Sow every 6.9 weeks. Last sowing by Jul 25 to harvest before frost.

For a dedicated fall crop, sow by Aug 04.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
1.1″/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 2.8" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 3.8" 0" ❄️ Dormant
Apr 3" 3.3" 0" ✅ Rainfall sufficient
May 3" 4.1" 0" ✅ Rainfall sufficient
Jun 3" 4.5" 0" ✅ Rainfall sufficient
Jul 3" 4.1" 0" ✅ Rainfall sufficient
Aug 3" 3.9" 0" ✅ Rainfall sufficient
Sep 3" 3.3" 0" ✅ Rainfall sufficient
Oct 3" 3.2" 0" ✅ Rainfall sufficient
Nov 3.1" 0" ❄️ Dormant
Dec 3.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Newport 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 ~1,435 GDD — county provides 3,403 GDD Excellent fit

Radicchio Planting Timeline — Newport County, RI

Radicchio Planting Calendar

Activity When Date Range
Start Indoors March 26 Mar 26 – Apr 9
Transplant Outdoors April 30 Apr 30 – May 14
Direct Sow April 16 Apr 16 – May 7
Harvest July 2 Jul 2 – Aug 6
Fall Sowing August 4 Aug 4 – Aug 18

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
July Harvest
August Fall Sowing Harvest
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 7a

📆 Growing Season

166 days in Newport County

Growing Tips for Radicchio in Newport County

Direct sow Radicchio outdoors after April 30 in Newport 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 Newport County, RI?

Newport County is in Zone 7a with an average last frost of April 30. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.

What planting zone is Newport County, RI?

Newport County, Rhode Island is in USDA Hardiness Zone 7a. The average last spring frost is April 30 and first fall frost is October 13.

🌱

Your Newport County Garden Planner — Free

A 24-page printable planner built for Newport County (Zone 7a). 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 Newport County, RI. 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.