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When to Plant Radicchio in McPherson County, SD

McPherson County, South Dakota Zone 4b May

Your May game plan for McPherson County, South Dakota

A quick May briefing for McPherson County, South Dakota gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 11
Avg. first frost September 27
Soil temp (4") 49°F
Watering Moderate
Pest pressure Low
Daylight 14.7 hrs
  1. Move radicchio into the garden

    Your last frost (May 11) has passed. These warm-season crops can handle outdoor soil now.

  2. Outdoor sowing time: radicchio

    Your soil is 49°F — warm enough for these to germinate without babying.

Looking ahead to 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.

McPherson County, South Dakota is in USDA Zone 4b. The average last spring frost is May 11 and the first fall frost is September 27, giving you a growing season of approximately 139 days.

At an elevation of 637 feet, McPherson County receives approximately 21.4 inches of rainfall annually with predominantly loam soil. Summer highs average 79°F, so choose short-season varieties of Radicchio to ensure they mature before fall.

McPherson County, SD (Zone 4b) Short season
139 days
Last Spring Frost May 11
139 growing days
First Fall Frost September 27

McPherson County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (45 days to spare)
Start indoors: Mar 21 Transplant: May 2 🍅 Harvest: Jul 4 – Aug 8
Recommended (50%) ✓ Fits season (41 days to spare)
Start indoors: Mar 30 Transplant: May 11 🍅 Harvest: Jul 13 – Aug 17
Safe Start (90%) ✓ Fits season (42 days to spare)
Start indoors: Apr 9 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 McPherson County

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

Soil pH

Your soil pH (6.7–7.9) is more alkaline than Radicchio prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.0%) — Radicchio will thrive.

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 139-day season

Sow every 6.9 weeks. Last sowing by Jul 09 to harvest before frost.

For a dedicated fall crop, sow by Jul 05.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.7″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 79 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 0.6" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 2.2" 0" ❄️ Dormant
May 3" 2.8" 0.2" 💧 Light watering
Jun 3" 3.3" 0" ✅ Rainfall sufficient
Jul 3" 2.8" 0.2" 💧 Light watering
Aug 3" 2.7" 0.3" 💧 Light watering
Sep 3" 1.9" 1.1" 💧 Light watering
Oct 1.5" 0" ❄️ Dormant
Nov 0.8" 0" ❄️ Dormant
Dec 0.5" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in McPherson 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 ~648 GDD — county provides 1,285 GDD Excellent fit

Radicchio Planting Timeline — McPherson County, SD

Radicchio Planting Calendar

Activity When Date Range
Start Indoors March 30 Mar 30 – Apr 13
Transplant Outdoors May 11 May 11 – May 25
Direct Sow May 4 May 4 – May 25
Harvest July 13 Jul 13 – Aug 17
Fall Sowing July 5 Jul 5 – Jul 19

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
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 4b

📆 Growing Season

139 days in McPherson County

Growing Tips for Radicchio in McPherson County

Direct sow Radicchio outdoors after May 11 in McPherson 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 McPherson County, SD?

McPherson County is in Zone 4b with an average last frost of May 11. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.

What planting zone is McPherson County, SD?

McPherson County, South Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 11 and first fall frost is September 27.

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Your McPherson County Garden Planner — Free

A 24-page printable planner built for McPherson 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.

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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 McPherson County, SD. 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.