Blog

When to Plant Radicchio in Chouteau County, MT

Chouteau County, Montana Zone 4a May

Chouteau County, Montana gardeners: here's your May plan

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

Avg. last frost May 12
Avg. first frost September 27
Soil temp (4") 37°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
  1. Time to transplant radicchio

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

  2. Outdoor sowing time: radicchio

    Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.

Looking ahead to June
  • 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.

Chouteau County, Montana is in USDA Zone 4a. The average last spring frost is May 12 and the first fall frost is September 27, giving you a growing season of approximately 138 days.

At an elevation of 5,753 feet, Chouteau County receives approximately 15 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Radicchio to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Radicchio successfully. Mulch heavily to conserve soil moisture.

Chouteau County, MT (Zone 4a) Short season
138 days
Last Spring Frost May 12
138 growing days
First Fall Frost September 27
Share this guide:

Chouteau County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (37 days to spare)
Start indoors: Mar 27 Transplant: May 8 🍅 Harvest: Jul 10 – Aug 14
Recommended (50%) ✓ Fits season (40 days to spare)
Start indoors: Mar 31 Transplant: May 12 🍅 Harvest: Jul 14 – Aug 18
Safe Start (90%) ✓ Fits season (33 days to spare)
Start indoors: Apr 21 Transplant: Jun 2 🍅 Harvest: Aug 4 – Sep 8

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 Chouteau County

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

Soil pH

Your soil pH (6.4–7.8) is more alkaline than Radicchio prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

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 138-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
0.5″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 359 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 1" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.4" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 3" 1.7" 1.3" 💧 Light watering
Jun 3" 1.2" 1.8" 🚿 Regular watering
Jul 3" 1.4" 1.6" 🚿 Regular watering
Aug 3" 1.8" 1.2" 💧 Light watering
Sep 3" 1.1" 1.9" 🚿 Regular watering
Oct 1.2" 0" ❄️ Dormant
Nov 0.9" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Chouteau 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 ~910 GDD — county provides 1,794 GDD Excellent fit

Radicchio Planting Timeline — Chouteau County, MT

Radicchio Planting Calendar

Activity When Date Range
Start Indoors March 31 Mar 31 – Apr 14
Transplant Outdoors May 12 May 12 – May 26
Direct Sow May 5 May 5 – May 26
Harvest July 14 Jul 14 – Aug 18
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 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 · 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

138 days in Chouteau County

Growing Tips for Radicchio in Chouteau County

Direct sow Radicchio outdoors after May 12 in Chouteau 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 Chouteau County, MT?

Chouteau County is in Zone 4a with an average last frost of May 12. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.

What planting zone is Chouteau County, MT?

Chouteau County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is May 12 and first fall frost is September 27.

🌱

Your Chouteau County Garden Planner — Free

A 24-page printable planner built for Chouteau 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 Chouteau 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.