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When to Plant Radicchio in Adams County, ND

Adams County, North Dakota Zone 4b May

May in Adams County, North Dakota — your action list

May is a pivotal month for Adams 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 14
Avg. first frost September 27
Soil temp (4") 53°F
Watering Moderate
Pest pressure Low
Daylight 14.8 hrs
  1. Move radicchio from tray to bed

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  2. Plant radicchio from seed, right in the garden

    Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.

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.

Adams County, North Dakota is in USDA Zone 4b. The average last spring frost is May 14 and the first fall frost is September 27, giving you a growing season of approximately 136 days.

At an elevation of 1,100 feet, Adams County receives approximately 27.4 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Radicchio to ensure they mature before fall.

Adams County, ND (Zone 4b) Short season
136 days
Last Spring Frost May 14
136 growing days
First Fall Frost September 27
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Adams County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (34 days to spare)
Start indoors: Mar 30 Transplant: May 11 🍅 Harvest: Jul 13 – Aug 17
Recommended (50%) ✓ Fits season (38 days to spare)
Start indoors: Apr 2 Transplant: May 14 🍅 Harvest: Jul 16 – Aug 20
Safe Start (90%) ✓ Fits season (42 days to spare)
Start indoors: Apr 13 Transplant: May 25 🍅 Harvest: Jul 27 – Aug 31

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 Adams County

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

Soil pH

Your soil pH (6.6–7.3) overlaps with Radicchio's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.2%). 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 136-day season

Sow every 6.9 weeks. Last sowing by Jul 09 to harvest before frost.

For a dedicated fall crop, sow by Jul 05.

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
Drought risk

Water stress score is 8/10 — 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 2" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 2.6" 0" ❄️ Dormant
May 3" 2.9" 0.1" 💧 Light watering
Jun 3" 1.8" 1.2" 💧 Light watering
Jul 3" 2.5" 0.5" 💧 Light watering
Aug 3" 3.1" 0" ✅ Rainfall sufficient
Sep 3" 2.5" 0.5" 💧 Light watering
Oct 2.2" 0" ❄️ Dormant
Nov 1.8" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Adams 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 ~752 GDD — county provides 1,462 GDD Excellent fit

Radicchio Planting Timeline — Adams County, ND

Radicchio Planting Calendar

Activity When Date Range
Start Indoors April 2 Apr 2 – Apr 16
Transplant Outdoors May 14 May 14 – May 28
Direct Sow May 7 May 7 – May 28
Harvest July 16 Jul 16 – Aug 20
Fall Sowing July 5 Jul 5 – Jul 19

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 4b

📆 Growing Season

136 days in Adams County

Growing Tips for Radicchio in Adams County

Direct sow Radicchio outdoors after May 14 in Adams 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 Adams County, ND?

Adams County is in Zone 4b with an average last frost of May 14. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.

What planting zone is Adams County, ND?

Adams County, North Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 14 and first fall frost is September 27.

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Your Adams County Garden Planner — Free

A 24-page printable planner built for Adams County (Zone 4b). 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 Adams 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.