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When to Plant Radicchio in Benewah County, ID

Benewah County, Idaho Zone 6b May

Benewah County, Idaho gardeners: here's your May plan

Welcome to May in Zone 6b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 8
Avg. first frost October 1
Soil temp (4") 44°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
  1. Move radicchio from tray to bed

    Frost risk is low now in Benewah County, Idaho. If you've been covering beds overnight, you can stop.

Before June arrives, get these ready
  • 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.

Benewah County, Idaho is in USDA Zone 6b. The average last spring frost is May 8 and the first fall frost is October 1, giving you a growing season of approximately 146 days.

At an elevation of 6,081 feet, Benewah County receives approximately 20.8 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Radicchio during the growing season.

Benewah County, ID (Zone 6b) Short season
146 days
Last Spring Frost May 8
146 growing days
First Fall Frost October 1

Benewah County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (46 days to spare)
Start indoors: Mar 25 Transplant: Apr 29 🍅 Harvest: Jul 1 – Aug 5
Recommended (50%) ✓ Fits season (48 days to spare)
Start indoors: Apr 3 Transplant: May 8 🍅 Harvest: Jul 10 – Aug 14
Safe Start (90%) ✓ Fits season (43 days to spare)
Start indoors: May 2 Transplant: Jun 6 🍅 Harvest: Aug 8 – Sep 12

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 Benewah County

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

Soil pH

Your soil pH (6.3–7.8) is more alkaline than Radicchio prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.2%). 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 146-day season

Sow every 6.9 weeks. Last sowing by Jul 13 to harvest before frost.

For a dedicated fall crop, sow by Jul 23.

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 158 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 1.3" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 3" 2.5" 0.5" 💧 Light watering
Jun 3" 1.5" 1.5" 🚿 Regular watering
Jul 3" 1.7" 1.3" 💧 Light watering
Aug 3" 2.2" 0.8" 💧 Light watering
Sep 3" 1.6" 1.4" 💧 Light watering
Oct 3" 1.8" 1.2" 💧 Light watering
Nov 1.6" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Benewah 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 ~1,225 GDD — county provides 2,555 GDD Excellent fit

Radicchio Planting Timeline — Benewah County, ID

Radicchio Planting Calendar

Activity When Date Range
Start Indoors April 3 Apr 3 – Apr 17
Transplant Outdoors May 8 May 8 – May 22
Direct Sow April 24 Apr 24 – May 15
Harvest July 10 Jul 10 – Aug 14
Fall Sowing July 23 Jul 23 – Aug 6

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

Month-by-Month Timeline

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

📆 Growing Season

146 days in Benewah County

Growing Tips for Radicchio in Benewah County

Direct sow Radicchio outdoors after May 08 in Benewah 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 Benewah County, ID?

Benewah County is in Zone 6b with an average last frost of May 8. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.

What planting zone is Benewah County, ID?

Benewah County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is May 8 and first fall frost is October 1.

🌱

Your Benewah County Garden Planner — Free

A 24-page printable planner built for Benewah County (Zone 6b). 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 Benewah County, ID. 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.