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When to Plant Radicchio in Lake County, MT

Lake County, Montana Zone 6a May

May in the garden — Lake County, Montana

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

Avg. last frost May 31
Avg. first frost September 12
Soil temp (4") 36°F
Watering High
Pest pressure Low
Daylight 14.9 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. Direct-sow radicchio

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

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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.

Lake County, Montana is in USDA Zone 6a. The average last spring frost is May 31 and the first fall frost is September 12, giving you a growing season of approximately 104 days.

At an elevation of 6,938 feet, Lake County receives approximately 12.8 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Radicchio during the growing season. With low rainfall, drip irrigation is essential for growing Radicchio successfully. Mulch heavily to conserve soil moisture.

Lake County, MT (Zone 6a) Short season
104 days
Last Spring Frost May 31
104 growing days
First Fall Frost September 12

Lake County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (11 days to spare)
Start indoors: Apr 15 Transplant: May 20 🍅 Harvest: Jul 22 – Aug 26
Recommended (50%) ✓ Fits season (6 days to spare)
Start indoors: Apr 26 Transplant: May 31 🍅 Harvest: Aug 2 – Sep 6
Safe Start (90%) ✓ Fits season (7 days to spare)
Start indoors: May 17 Transplant: Jun 21 🍅 Harvest: Aug 23 – Sep 27

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 Lake County

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

Soil pH

Your soil pH (6.6–7.7) is more alkaline than Radicchio prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Radicchio.

How to Plant Radicchio

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

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.5″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 203 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" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 3" 1.4" 1.6" 🚿 Regular watering
Jun 3" 0.9" 2.1" 🚿 Regular watering
Jul 3" 1.3" 1.7" 🚿 Regular watering
Aug 3" 1.2" 1.8" 🚿 Regular watering
Sep 3" 1.1" 1.9" 🚿 Regular watering
Oct 1.1" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Lake 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 ~962 GDD — county provides 1,430 GDD Excellent fit

Radicchio Planting Timeline — Lake County, MT

Radicchio Planting Calendar

Activity When Date Range
Start Indoors April 26 Apr 26 – May 10
Transplant Outdoors May 31 May 31 – Jun 14
Direct Sow May 17 May 17 – Jun 7
Harvest August 2 Aug 2 – Sep 6
Fall Sowing July 4 Jul 4 – Jul 18

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Start Indoors Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July Fall Sowing
August Harvest
September Harvest
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 6a

📆 Growing Season

104 days in Lake County

Growing Tips for Radicchio in Lake County

Direct sow Radicchio outdoors after May 31 in Lake 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 Lake County, MT?

Lake County is in Zone 6a with an average last frost of May 31. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lake County, MT?

Lake County, Montana is in USDA Hardiness Zone 6a. The average last spring frost is May 31 and first fall frost is September 12.

🌱

Your Lake County Garden Planner — Free

A 24-page printable planner built for Lake County (Zone 6a). 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 Lake County, MT. Local conditions may vary. Last updated: May 2026.

Sources & credits

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