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When to Plant Radicchio in Dawson County, MT

Dawson County, Montana Zone 4a May

Your May gardening checklist

Here's what deserves your attention in Dawson County, Montana this month. Everything below is tailored to Zone 4a and timed around your local frost dates.

Avg. last frost May 14
Avg. first frost September 22
Soil temp (4") 36°F
Watering Moderate
Pest pressure Low
Daylight 14.9 hrs
  1. Plant out radicchio

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Scatter radicchio into prepared beds

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

June will be here before you know it — start on
  • Starting indoors: radicchio
  • Fall sowing: 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.

Dawson County, Montana is in USDA Zone 4a. The average last spring frost is May 14 and the first fall frost is September 22, giving you a growing season of approximately 131 days.

At an elevation of 6,445 feet, Dawson County receives approximately 21.9 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.

Dawson County, MT (Zone 4a) Short season
131 days
Last Spring Frost May 14
131 growing days
First Fall Frost September 22
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Dawson County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (33 days to spare)
Start indoors: Mar 29 Transplant: May 10 🍅 Harvest: Jul 12 – Aug 16
Recommended (50%) ✓ Fits season (33 days to spare)
Start indoors: Apr 2 Transplant: May 14 🍅 Harvest: Jul 16 – Aug 20
Safe Start (90%) ✓ Fits season (36 days to spare)
Start indoors: Apr 15 Transplant: May 27 🍅 Harvest: Jul 29 – Sep 2

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 Dawson County

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

Soil pH

Your soil pH (6.8–8.2) is more alkaline than Radicchio prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Dawson 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 (2.6%). 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 131-day season

Sow every 6.9 weeks. Last sowing by Jul 04 to harvest before frost.

For a dedicated fall crop, sow by Jun 30.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 291 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 1.8" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 3" 2.8" 0.2" 💧 Light watering
Jun 3" 1.4" 1.6" 🚿 Regular watering
Jul 3" 2" 1" 💧 Light watering
Aug 3" 2.1" 0.9" 💧 Light watering
Sep 3" 2" 1" 💧 Light watering
Oct 1.8" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Dawson 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 1,310 GDD Excellent fit

Radicchio Planting Timeline — Dawson County, MT

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 June 30 Jun 30 – Jul 14

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 Fall Sowing
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 · Only during dry spells

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4a

📆 Growing Season

131 days in Dawson County

Growing Tips for Radicchio in Dawson County

Direct sow Radicchio outdoors after May 14 in Dawson 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 Dawson County, MT?

Dawson County is in Zone 4a 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 Dawson County, MT?

Dawson County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is May 14 and first fall frost is September 22.

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Your Dawson County Garden Planner — Free

A 24-page printable planner built for Dawson 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 Dawson County, MT. 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.