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When to Plant Radicchio in Cascade County, MT

Cascade County, Montana Zone 4b May

This month in Cascade County, Montana

Each item below is timed to Cascade County, Montana's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 19
Avg. first frost September 21
Soil temp (4") 33°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
  1. Move radicchio into the garden

    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. Put radicchio seeds straight in the ground

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

Get ahead of June
  • 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.

Cascade County, Montana is in USDA Zone 4b. The average last spring frost is May 19 and the first fall frost is September 21, giving you a growing season of approximately 125 days.

At an elevation of 6,585 feet, Cascade County receives approximately 21.8 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Radicchio to ensure they mature before fall.

Cascade County, MT (Zone 4b) Short season
125 days
Last Spring Frost May 19
125 growing days
First Fall Frost September 21

Cascade 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 (26 days to spare)
Start indoors: Mar 31 Transplant: May 12 🍅 Harvest: Jul 14 – Aug 18
Recommended (50%) ✓ Fits season (27 days to spare)
Start indoors: Apr 7 Transplant: May 19 🍅 Harvest: Jul 21 – Aug 25
Safe Start (90%) ✓ Fits season (17 days to spare)
Start indoors: May 1 Transplant: Jun 12 🍅 Harvest: Aug 14 – Sep 18

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 Cascade 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 Cascade 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 (2.7%). 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 125-day season

Sow every 6.9 weeks. Last sowing by Jul 03 to harvest before frost.

For a dedicated fall crop, sow by Jun 29.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.7″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 237 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 1.8" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 3" 2.3" 0.7" 💧 Light watering
Jun 3" 1.5" 1.5" 🚿 Regular watering
Jul 3" 2.1" 0.9" 💧 Light watering
Aug 3" 2" 1" 💧 Light watering
Sep 3" 1.8" 1.2" 💧 Light watering
Oct 2.1" 0" ❄️ Dormant
Nov 1.6" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Cascade 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 ~858 GDD — county provides 1,531 GDD Excellent fit

Radicchio Planting Timeline — Cascade County, MT

Radicchio Planting Calendar

Activity When Date Range
Start Indoors April 7 Apr 7 – Apr 21
Transplant Outdoors May 19 May 19 – Jun 2
Direct Sow May 12 May 12 – Jun 2
Harvest July 21 Jul 21 – Aug 25
Fall Sowing June 29 Jun 29 – Jul 13

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 Transplant Outdoors Direct Sow Fall Sowing
July Fall Sowing Harvest
August Harvest
September
October
November
December

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 4b

📆 Growing Season

125 days in Cascade County

Growing Tips for Radicchio in Cascade County

Direct sow Radicchio outdoors after May 19 in Cascade 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 Cascade County, MT?

Cascade County is in Zone 4b with an average last frost of May 19. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cascade County, MT?

Cascade County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 19 and first fall frost is September 21.

🌱

Your Cascade County Garden Planner — Free

A 24-page printable planner built for Cascade 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.

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 Cascade 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.