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When to Plant Kohlrabi in Ozaukee County, WI

Ozaukee County, Wisconsin Zone 5b May

May in the garden — Ozaukee County, Wisconsin

We've pulled the most time-sensitive tasks for Ozaukee County, Wisconsin this May and put them front and centre. Tackle them in order.

Avg. last frost April 27
Avg. first frost October 11
Soil temp (4") 56°F
Watering Moderate
Pest pressure Low
Daylight 14.5 hrs
To set up a strong June, finish these tasks
  • 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.

Ozaukee County, Wisconsin is in USDA Zone 5b. The average last spring frost is April 27 and the first fall frost is October 11, giving you a growing season of approximately 167 days.

At an elevation of 1,277 feet, Ozaukee County receives approximately 32.5 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.

Ozaukee County, WI (Zone 5b) Moderate season
167 days
Last Spring Frost April 27
167 growing days
First Fall Frost October 11

Ozaukee 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 (81 days to spare)
Start indoors: Mar 20 Transplant: Apr 24 🍅 Harvest: Jun 12 – Jul 17
Recommended (50%) ✓ Fits season (83 days to spare)
Start indoors: Mar 23 Transplant: Apr 27 🍅 Harvest: Jun 15 – Jul 20
Safe Start (90%) ✓ Fits season (82 days to spare)
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Jul 1 – Aug 5

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 Ozaukee County

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

Soil pH

Your soil pH (6.1–7.1) is within Kohlrabi's preferred range (6.0–7.5).

Soil Texture

The silt loam soil in Ozaukee 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 (4.7%) — 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 167-day season

Sow every 5.1 weeks. Last sowing by Aug 07 to harvest before frost.

For a dedicated fall crop, sow by Aug 02.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.8″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 138 gal / 100 sq ft

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 1.4" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 3" 2.7" 0.3" 💧 Light watering
May 3" 3.3" 0" ✅ Rainfall sufficient
Jun 3" 3.9" 0" ✅ Rainfall sufficient
Jul 3" 4" 0" ✅ Rainfall sufficient
Aug 3" 3.8" 0" ✅ Rainfall sufficient
Sep 3" 2.9" 0.1" 💧 Light watering
Oct 3" 2.5" 0.5" 💧 Light watering
Nov 2.3" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Ozaukee 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 2,171 GDD Excellent fit

Kohlrabi Planting Timeline — Ozaukee County, WI

Kohlrabi Planting Calendar

Activity When Date Range
Start Indoors March 23 Mar 23 – Apr 6
Transplant Outdoors April 27 Apr 27 – May 11
Direct Sow April 13 Apr 13 – May 4
Harvest June 15 Jun 15 – Jul 20
Fall Sowing August 2 Aug 2 – Aug 16

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: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

167 days in Ozaukee County

Growing Tips for Kohlrabi in Ozaukee County

Direct sow Kohlrabi outdoors after April 27 in Ozaukee County when soil has warmed and frost danger has passed.

Your generous 167.0-day season in Ozaukee 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 Ozaukee County, WI?

Ozaukee County is in Zone 5b with an average last frost of April 27. Plan your Kohlrabi planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ozaukee County, WI?

Ozaukee County, Wisconsin is in USDA Hardiness Zone 5b. The average last spring frost is April 27 and first fall frost is October 11.

🌱

Your Ozaukee County Garden Planner — Free

A 24-page printable planner built for Ozaukee 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 Ozaukee 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.