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When to Plant Radish in Montcalm County, MI

Montcalm County, Michigan Zone 5b May

What to do in May

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

Avg. last frost May 4
Avg. first frost October 10
Soil temp (4") 56°F
Watering Moderate
Pest pressure Low
Daylight 14.5 hrs
  1. Harvest radish as they ripen

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

Get ahead of June
  • First harvests: radish

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Radishes are one of the fastest-growing vegetables, with some varieties ready in under a month. They come in round, elongated, and large winter types.

Montcalm County, Michigan is in USDA Zone 5b. The average last spring frost is May 4 and the first fall frost is October 10, giving you a growing season of approximately 159 days.

At an elevation of 1,377 feet, Montcalm County receives approximately 33.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Radish during the growing season.

Montcalm County, MI (Zone 5b) Moderate season
159 days
Last Spring Frost May 4
159 growing days
First Fall Frost October 10
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Montcalm County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (108 days to spare)
Transplant: Apr 28 🍅 Harvest: May 26 – Jun 16
Recommended (50%) ✓ Fits season (110 days to spare)
Transplant: May 4 🍅 Harvest: Jun 1 – Jun 22
Safe Start (90%) ✓ Fits season (112 days to spare)
Transplant: May 22 🍅 Harvest: Jun 19 – Jul 10

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 Montcalm County

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

Soil pH

Your soil pH (6.2–7.2) overlaps with Radish's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Radish.

Organic Matter

Organic matter is excellent (4.8%) — Radish will thrive.

How to Plant Radish

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

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

Succession Planting Radish

9
successive plantings in your 159-day season

Sow every 2.4 weeks. Last sowing by Sep 05 to harvest before frost.

For a dedicated fall crop, sow by Aug 01.

Plant Water Budget

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

Monthly Watering Guide for Radish

Radish needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Radish Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 2.9" 0" ❄️ Dormant
May 2.2" 3.6" 0" ✅ Rainfall sufficient
Jun 2.2" 4.6" 0" ✅ Rainfall sufficient
Jul 2.2" 3.8" 0" ✅ Rainfall sufficient
Aug 2.2" 3.2" 0" ✅ Rainfall sufficient
Sep 2.2" 3" 0" ✅ Rainfall sufficient
Oct 2.2" 3" 0" ✅ Rainfall sufficient
Nov 2.4" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Montcalm County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Radish 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.

Radish needs ~435 GDD — county provides 2,424 GDD Excellent fit

Radish Planting Timeline — Montcalm County, MI

Radish Planting Calendar

Activity When Date Range
Direct Sow April 20 Apr 20 – May 11
Harvest May 18 May 18 – Jun 8
Fall Sowing August 1 Aug 1 – Aug 15

Plant 0.5" deep · 2" apart · Rows 6" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

22–35 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

159 days in Montcalm County

Growing Tips for Radish in Montcalm County

Direct sow Radish outdoors after May 04 in Montcalm County when soil has warmed and frost danger has passed.

Your generous 159.0-day season in Montcalm County allows multiple plantings of Radish. Sow every 11.0 days for continuous harvest.

Common pests for Radish in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow every 1-2 weeks for continuous harvest. Do not transplant. Harvest spring radishes promptly to prevent them from becoming pithy and hot.

Companion Planting

Good Companions

Avoid Planting Near

  • Hyssop

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Radish in Montcalm County, MI?

Montcalm County is in Zone 5b with an average last frost of May 4. Plan your Radish planting based on this frost date — see the calendar above for exact timing.

What planting zone is Montcalm County, MI?

Montcalm County, Michigan is in USDA Hardiness Zone 5b. The average last spring frost is May 4 and first fall frost is October 10.

🌱

Your Montcalm County Garden Planner — Free

A 24-page printable planner built for Montcalm County (Zone 5b). 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 Montcalm County, MI. 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.