Blog

When to Plant Radicchio in Cass County, ND

Cass County, North Dakota Zone 4a May

Cass County, North Dakota gardeners: here's your May plan

May is a pivotal month for Cass County, North Dakota gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 11
Avg. first frost October 2
Soil temp (4") 53°F
Watering Low
Pest pressure Low
Daylight 14.8 hrs
  1. Move radicchio into the garden

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

  2. Sow radicchio where they'll grow

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

Before June arrives, get these ready
  • Starting indoors: 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.

Cass County, North Dakota is in USDA Zone 4a. The average last spring frost is May 11 and the first fall frost is October 2, giving you a growing season of approximately 144 days.

At an elevation of 839 feet, Cass County receives approximately 33.1 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Radicchio to ensure they mature before fall.

Cass County, ND (Zone 4a) Short season
144 days
Last Spring Frost May 11
144 growing days
First Fall Frost October 2
Share this guide:

Cass County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (50 days to spare)
Start indoors: Mar 21 Transplant: May 2 🍅 Harvest: Jul 4 – Aug 8
Recommended (50%) ✓ Fits season (46 days to spare)
Start indoors: Mar 30 Transplant: May 11 🍅 Harvest: Jul 13 – Aug 17
Safe Start (90%) ✓ Fits season (48 days to spare)
Start indoors: Apr 10 Transplant: May 22 🍅 Harvest: Jul 24 – Aug 28

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 Cass County

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

Soil pH

Your soil pH (6.5–7.6) is more alkaline than Radicchio prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.4%). Annual compost additions will help Radicchio.

How to Plant Radicchio

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Radicchio

2
successive plantings in your 144-day season

Sow every 6.9 weeks. Last sowing by Jul 14 to harvest before frost.

For a dedicated fall crop, sow by Jul 10.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
1.0″/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 0.8" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 3.6" 0" ❄️ Dormant
May 3" 4.2" 0" ✅ Rainfall sufficient
Jun 3" 5.8" 0" ✅ Rainfall sufficient
Jul 3" 3.9" 0" ✅ Rainfall sufficient
Aug 3" 4.3" 0" ✅ Rainfall sufficient
Sep 3" 2.8" 0.2" 💧 Light watering
Oct 3" 2.3" 0.7" 💧 Light watering
Nov 1.1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Cass 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 ~700 GDD — county provides 1,440 GDD Excellent fit

Radicchio Planting Timeline — Cass County, ND

Radicchio Planting Calendar

Activity When Date Range
Start Indoors March 30 Mar 30 – Apr 13
Transplant Outdoors May 11 May 11 – May 25
Direct Sow May 4 May 4 – May 25
Harvest July 13 Jul 13 – Aug 17
Fall Sowing July 10 Jul 10 – Jul 24

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
May Transplant Outdoors Direct Sow
June
July Fall Sowing Harvest
August Harvest
September
October
November
December
Share this guide:

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_alkaline

🗺️ USDA Zone

Zone 4a

📆 Growing Season

144 days in Cass County

Growing Tips for Radicchio in Cass County

Direct sow Radicchio outdoors after May 11 in Cass 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 Cass County, ND?

Cass County is in Zone 4a with an average last frost of May 11. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cass County, ND?

Cass County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 11 and first fall frost is October 2.

🌱

Your Cass County Garden Planner — Free

A 24-page printable planner built for Cass County (Zone 4a). 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 Cass County, ND. 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.