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When to Plant Radicchio in Marquette County, WI

Marquette County, Wisconsin Zone 5a May

May to-do list for Marquette County, Wisconsin

May is a pivotal month for Marquette County, Wisconsin gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 3
Avg. first frost October 7
Soil temp (4") 54°F
Watering Low
Pest pressure Low
Daylight 14.5 hrs
  1. Transplant radicchio outside

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

Coming up in June — start thinking about
  • 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.

Marquette County, Wisconsin is in USDA Zone 5a. The average last spring frost is May 3 and the first fall frost is October 7, giving you a growing season of approximately 157 days.

At an elevation of 728 feet, Marquette County receives approximately 38.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Radicchio to ensure they mature before fall.

Marquette County, WI (Zone 5a) Moderate season
157 days
Last Spring Frost May 3
157 growing days
First Fall Frost October 7
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Marquette County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (59 days to spare)
Start indoors: Mar 24 Transplant: Apr 28 🍅 Harvest: Jun 30 – Aug 4
Recommended (50%) ✓ Fits season (59 days to spare)
Start indoors: Mar 29 Transplant: May 3 🍅 Harvest: Jul 5 – Aug 9
Safe Start (90%) ✓ Fits season (51 days to spare)
Start indoors: Apr 16 Transplant: May 21 🍅 Harvest: Jul 23 – Aug 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 Marquette County

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

Soil pH

Your soil pH (6.1–7.1) overlaps with Radicchio's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.0%) — Radicchio will thrive.

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

3
successive plantings in your 157-day season

Sow every 6.9 weeks. Last sowing by Jul 19 to harvest before frost.

For a dedicated fall crop, sow by Jul 29.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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 1.7" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 3.5" 0" ❄️ Dormant
May 3" 4.4" 0" ✅ Rainfall sufficient
Jun 3" 4.4" 0" ✅ Rainfall sufficient
Jul 3" 4.5" 0" ✅ Rainfall sufficient
Aug 3" 3.9" 0" ✅ Rainfall sufficient
Sep 3" 3.4" 0" ✅ Rainfall sufficient
Oct 3" 3.4" 0" ✅ Rainfall sufficient
Nov 2.5" 0" ❄️ Dormant
Dec 2.5" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Marquette 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 ~752 GDD — county provides 1,687 GDD Excellent fit

Radicchio Planting Timeline — Marquette County, WI

Radicchio Planting Calendar

Activity When Date Range
Start Indoors March 29 Mar 29 – Apr 12
Transplant Outdoors May 3 May 3 – May 17
Direct Sow April 19 Apr 19 – May 10
Harvest July 5 Jul 5 – Aug 9
Fall Sowing July 29 Jul 29 – Aug 12

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Direct Sow
May Transplant Outdoors Direct Sow
June
July Fall Sowing Harvest
August Fall Sowing Harvest
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

157 days in Marquette County

Growing Tips for Radicchio in Marquette County

Direct sow Radicchio outdoors after May 03 in Marquette 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 Marquette County, WI?

Marquette County is in Zone 5a with an average last frost of May 3. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.

What planting zone is Marquette County, WI?

Marquette County, Wisconsin is in USDA Hardiness Zone 5a. The average last spring frost is May 3 and first fall frost is October 7.

🌱

Your Marquette County Garden Planner — Free

A 24-page printable planner built for Marquette 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 Marquette County, WI. 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.