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When to Plant Cardoon in Newport County, RI

Newport County, Rhode Island Zone 7a May

May in the garden — Newport County, Rhode Island

Your garden in Newport County, Rhode Island is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost April 30
Avg. first frost October 13
Soil temp (4") 68°F
Watering Low
Pest pressure Moderate
Daylight 14.3 hrs
  1. Plant out cardoon

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

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Cardoon is a large thistle relative of the artichoke, grown for its edible leaf stalks. It has dramatic silvery foliage and makes a striking ornamental as well.

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 Cardoon 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) ✗ May not fit
Transplant: May 8 🍅 Harvest: Sep 11 – Oct 23
Recommended (50%) ✗ May not fit
Transplant: May 14 🍅 Harvest: Sep 17 – Oct 29
Safe Start (90%) ✗ May not fit
Transplant: May 29 🍅 Harvest: Oct 2 – Nov 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 Newport County

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

Soil pH

Your soil pH (4.8–6.7) is more acidic than Cardoon prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.8%). Annual compost additions will help Cardoon.

How to Plant Cardoon

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Cardoon

Cardoon needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Cardoon Needs Rainfall You Supplement Action
Jan 2.8" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 3.8" 0" ❄️ Dormant
Apr 4.3" 3.3" 1" 💧 Light watering
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 4.5" 0" ✅ Rainfall sufficient
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 3.3" 1" 💧 Light watering
Oct 4.3" 3.2" 1.1" 💧 Light watering
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.

Cardoon 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.

Cardoon needs ~2,768 GDD — county provides 3,403 GDD Good fit

Cardoon Planting Timeline — Newport County, RI

Cardoon Planting Calendar

Activity When Date Range
Transplant Outdoors May 14 May 14 – May 28
Harvest September 17 Sep 17 – Oct 29

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July
August
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

120–150 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 7a

📆 Growing Season

166 days in Newport County

Growing Tips for Cardoon in Newport County

Direct sow Cardoon outdoors after April 30 in Newport County when soil has warmed and frost danger has passed.

Common pests for Cardoon in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Blanch stalks by wrapping with cardboard or tying leaves together 3-4 weeks before harvest. Provide deep, rich soil and consistent moisture. Protect from hard frost.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cardoon in Newport County, RI?

Newport County is in Zone 7a with an average last frost of April 30. Plan your Cardoon 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.

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 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.