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When to Plant Kohlrabi in Mille Lacs County, MN

Mille Lacs County, Minnesota Zone 4a May

Mille Lacs County, Minnesota gardeners: here's your May plan

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

Avg. last frost May 1
Avg. first frost October 6
Soil temp (4") 53°F
Watering Moderate
Pest pressure Low
Daylight 14.7 hrs
  1. Transplant kohlrabi outside

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

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.

Mille Lacs County, Minnesota is in USDA Zone 4a. The average last spring frost is May 1 and the first fall frost is October 6, giving you a growing season of approximately 158 days.

At an elevation of 874 feet, Mille Lacs County receives approximately 31.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Kohlrabi to ensure they mature before fall.

Mille Lacs County, MN (Zone 4a) Moderate season
158 days
Last Spring Frost May 1
158 growing days
First Fall Frost October 6

Mille Lacs County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (72 days to spare)
Start indoors: Mar 14 Transplant: Apr 25 🍅 Harvest: Jun 13 – Jul 18
Recommended (50%) ✓ Fits season (74 days to spare)
Start indoors: Mar 20 Transplant: May 1 🍅 Harvest: Jun 19 – Jul 24
Safe Start (90%) ✓ Fits season (70 days to spare)
Start indoors: Apr 6 Transplant: May 18 🍅 Harvest: Jul 6 – Aug 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 Mille Lacs County

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

Soil pH

Your soil pH (5.9–7.3) overlaps with Kohlrabi's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.4%) — Kohlrabi will thrive.

How to Plant Kohlrabi

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

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Kohlrabi

4
successive plantings in your 158-day season

Sow every 5.1 weeks. Last sowing by Aug 02 to harvest before frost.

For a dedicated fall crop, sow by Jul 14.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 1.3" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 3" 0" ❄️ Dormant
May 3" 3.3" 0" ✅ Rainfall sufficient
Jun 3" 3.9" 0" ✅ Rainfall sufficient
Jul 3" 3.6" 0" ✅ Rainfall sufficient
Aug 3" 3.4" 0" ✅ Rainfall sufficient
Sep 3" 2.9" 0.1" 💧 Light watering
Oct 3" 2.1" 0.9" 💧 Light watering
Nov 2.2" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Mille Lacs 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 ~550 GDD — county provides 1,580 GDD Excellent fit

Kohlrabi Planting Timeline — Mille Lacs County, MN

Kohlrabi Planting Calendar

Activity When Date Range
Start Indoors March 20 Mar 20 – Apr 3
Transplant Outdoors May 1 May 1 – May 15
Direct Sow April 24 Apr 24 – May 15
Harvest June 19 Jun 19 – Jul 24
Fall Sowing July 14 Jul 14 – Jul 28

Plant 0.5" deep · 4" 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 Harvest
July Fall Sowing Harvest
August
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

45–65 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

158 days in Mille Lacs County

Growing Tips for Kohlrabi in Mille Lacs County

Direct sow Kohlrabi outdoors after May 01 in Mille Lacs County when soil has warmed and frost danger has passed.

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 Mille Lacs County, MN?

Mille Lacs County is in Zone 4a with an average last frost of May 1. Plan your Kohlrabi planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mille Lacs County, MN?

Mille Lacs County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 1 and first fall frost is October 6.

🌱

Your Mille Lacs County Garden Planner — Free

A 24-page printable planner built for Mille Lacs County (Zone 4a). 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 Mille Lacs County, MN. 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.