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When to Plant Radicchio in Lincoln County, MT

Lincoln County, Montana Zone 5a May

May in Lincoln County, Montana — your action list

Welcome to May in Zone 5a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 16
Avg. first frost September 23
Soil temp (4") 37°F
Watering High
Pest pressure Low
Daylight 15 hrs
  1. Set out radicchio seedlings

    Your last frost (May 16) has passed. These warm-season crops can handle outdoor soil now.

  2. Outdoor sowing time: radicchio

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

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.

Lincoln County, Montana is in USDA Zone 5a. The average last spring frost is May 16 and the first fall frost is September 23, giving you a growing season of approximately 130 days.

At an elevation of 6,794 feet, Lincoln County receives approximately 18.1 inches of rainfall annually with predominantly loam soil. Summer highs average 86°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.

Lincoln County, MT (Zone 5a) Short season
130 days
Last Spring Frost May 16
130 growing days
First Fall Frost September 23

Lincoln County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (37 days to spare)
Start indoors: Mar 31 Transplant: May 5 🍅 Harvest: Jul 7 – Aug 11
Recommended (50%) ✓ Fits season (32 days to spare)
Start indoors: Apr 11 Transplant: May 16 🍅 Harvest: Jul 18 – Aug 22
Safe Start (90%) ✓ Fits season (30 days to spare)
Start indoors: May 5 Transplant: Jun 9 🍅 Harvest: Aug 11 – Sep 15

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 Lincoln County

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

Soil pH

Your soil pH (6.8–7.7) is more alkaline than Radicchio prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Lincoln 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 10 weeks before your first frost date for a fall harvest.

Succession Planting Radicchio

2
successive plantings in your 130-day season

Sow every 6.9 weeks. Last sowing by Jul 05 to harvest before frost.

For a dedicated fall crop, sow by Jul 15.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.6″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 160 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 1.4" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 1.9" 0" ❄️ Dormant
May 3" 2.1" 0.9" 💧 Light watering
Jun 3" 1.2" 1.8" 🚿 Regular watering
Jul 3" 1.8" 1.2" 💧 Light watering
Aug 3" 1.6" 1.4" 💧 Light watering
Sep 3" 1.5" 1.5" 🚿 Regular watering
Oct 1.6" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Lincoln 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 ~1,015 GDD — county provides 1,885 GDD Excellent fit

Radicchio Planting Timeline — Lincoln County, MT

Radicchio Planting Calendar

Activity When Date Range
Start Indoors April 11 Apr 11 – Apr 25
Transplant Outdoors May 16 May 16 – May 30
Direct Sow May 2 May 2 – May 23
Harvest July 18 Jul 18 – Aug 22
Fall Sowing July 15 Jul 15 – Jul 29

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

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 5a

📆 Growing Season

130 days in Lincoln County

Growing Tips for Radicchio in Lincoln County

Direct sow Radicchio outdoors after May 16 in Lincoln 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 Lincoln County, MT?

Lincoln County is in Zone 5a with an average last frost of May 16. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lincoln County, MT?

Lincoln County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is May 16 and first fall frost is September 23.

🌱

Your Lincoln County Garden Planner — Free

A 24-page printable planner built for Lincoln County (Zone 5a). 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 Lincoln 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.