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When to Plant Kohlrabi in Clinton County, MI

Clinton County, Michigan Zone 6a May

Your May game plan for Clinton County, Michigan

Your Clinton County, Michigan garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost April 30
Avg. first frost October 13
Soil temp (4") 58°F
Watering Low
Pest pressure Low
Daylight 14.5 hrs
June will be here before you know it — start on
  • Starting indoors: kohlrabi
  • First harvests: kohlrabi

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Kohlrabi is an unusual brassica that forms a swollen stem above ground with a mild, sweet turnip-like flavor. Both the bulb and tender leaves are edible.

Clinton County, Michigan is in USDA Zone 6a. The average last spring frost is April 30 and the first fall frost is October 13, giving you a growing season of approximately 166 days.

At an elevation of 519 feet, Clinton County receives approximately 34.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Kohlrabi to ensure they mature before fall.

Clinton County, MI (Zone 6a) Moderate season
166 days
Last Spring Frost April 30
166 growing days
First Fall Frost October 13

Clinton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (78 days to spare)
Start indoors: Mar 23 Transplant: Apr 27 🍅 Harvest: Jun 15 – Jul 20
Recommended (50%) ✓ Fits season (82 days to spare)
Start indoors: Mar 26 Transplant: Apr 30 🍅 Harvest: Jun 18 – Jul 23
Safe Start (90%) ✓ Fits season (78 days to spare)
Start indoors: Apr 15 Transplant: May 20 🍅 Harvest: Jul 8 – Aug 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 Clinton County

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

Soil pH

Your soil pH (5.9–6.7) overlaps with Kohlrabi's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Kohlrabi.

Organic Matter

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

How to Plant Kohlrabi

0.5"
Planting Depth
4"
Between Plants
12"
Between Rows

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

Succession Planting Kohlrabi

4
successive plantings in your 166-day season

Sow every 5.1 weeks. Last sowing by Aug 09 to harvest before frost.

For a dedicated fall crop, sow by Aug 04.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 84 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Kohlrabi

Kohlrabi needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Kohlrabi Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 3" 2.9" 0.1" 💧 Light watering
May 3" 3.8" 0" ✅ Rainfall sufficient
Jun 3" 4.1" 0" ✅ Rainfall sufficient
Jul 3" 3.7" 0" ✅ Rainfall sufficient
Aug 3" 3.9" 0" ✅ Rainfall sufficient
Sep 3" 3" 0" ✅ Rainfall sufficient
Oct 3" 2.7" 0.3" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

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

Kohlrabi 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.

Kohlrabi needs ~715 GDD — county provides 2,158 GDD Excellent fit

Kohlrabi Planting Timeline — Clinton County, MI

Kohlrabi Planting Calendar

Activity When Date Range
Start Indoors March 26 Mar 26 – Apr 9
Transplant Outdoors April 30 Apr 30 – May 14
Direct Sow April 16 Apr 16 – May 7
Harvest June 18 Jun 18 – Jul 23
Fall Sowing August 4 Aug 4 – Aug 18

Plant 0.5" deep · 4" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · Only during dry spells

📅 Days to Maturity

45–65 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

166 days in Clinton County

Growing Tips for Kohlrabi in Clinton County

Direct sow Kohlrabi outdoors after April 30 in Clinton County when soil has warmed and frost danger has passed.

Your generous 166.0-day season in Clinton County allows multiple plantings of Kohlrabi. Sow every 22.0 days for continuous harvest.

Common pests for Kohlrabi 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 in spring or fall. Harvest when bulbs are 2-3 inches in diameter for best texture and flavor. Larger bulbs may become woody and fibrous.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Kohlrabi in Clinton County, MI?

Clinton County is in Zone 6a with an average last frost of April 30. Plan your Kohlrabi planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clinton County, MI?

Clinton County, Michigan is in USDA Hardiness Zone 6a. The average last spring frost is April 30 and first fall frost is October 13.

🌱

Your Clinton County Garden Planner — Free

A 24-page printable planner built for Clinton County (Zone 6a). 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 Clinton 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.