When to Plant Kohlrabi in Douglas County, MN
Your May planting checklist for Douglas County, Minnesota
May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Douglas County, Minnesota.
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Harden off and plant kohlrabi
Frost risk is low now in Douglas County, Minnesota. If you've been covering beds overnight, you can stop.
Looking ahead to June
- Starting indoors: kohlrabi
- First harvests: kohlrabi
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.
Douglas County, Minnesota is in USDA Zone 4b. The average last spring frost is May 3 and the first fall frost is October 4, giving you a growing season of approximately 154 days.
At an elevation of 1,010 feet, Douglas County receives approximately 37.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Kohlrabi to ensure they mature before fall.
Douglas County Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-6.9
Drainage
Well Drained
Plant Planting Risk Windows
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 Douglas County
How your county's soil matches Kohlrabi's growing requirements.
Soil pH
Your soil pH (5.8–6.9) overlaps with Kohlrabi's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Douglas County is excellent for Kohlrabi — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.2%) — Kohlrabi will thrive.
How to Plant Kohlrabi
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Succession Planting Kohlrabi
Sow every 5.1 weeks. Last sowing by Jul 31 to harvest before frost.
For a dedicated fall crop, sow by Jul 12.
Plant Water Budget
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 | — | 2.3" | 0" | ❄️ Dormant |
| Apr | — | 3.4" | 0" | ❄️ Dormant |
| May | 3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Jun | 3" | 5.2" | 0" | ✅ Rainfall sufficient |
| Jul | 3" | 4" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 4" | 0" | ✅ Rainfall sufficient |
| Sep | 3" | 2.9" | 0.1" | 💧 Light watering |
| Oct | 3" | 2.9" | 0.1" | 💧 Light watering |
| Nov | — | 2.8" | 0" | ❄️ Dormant |
| Dec | — | 1.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Douglas 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 Planting Timeline — Douglas County, MN
Kohlrabi Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 22 | Mar 22 – Apr 5 |
| Transplant Outdoors | May 3 | May 3 – May 17 |
| Direct Sow | April 26 | Apr 26 – May 17 |
| Harvest | June 21 | Jun 21 – Jul 26 |
| Fall Sowing | July 12 | Jul 12 – Jul 26 |
Plant 0.5" deep · 4" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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 4b
📆 Growing Season
154 days in Douglas County
Growing Tips for Kohlrabi in Douglas County
Direct sow Kohlrabi outdoors after May 03 in Douglas 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
Check more plant combinations with our Companion Planting Checker →
Kohlrabi in Other Locations
Frequently Asked Questions
When should I plant Kohlrabi in Douglas County, MN?
Douglas County is in Zone 4b with an average last frost of May 3. Plan your Kohlrabi planting based on this frost date — see the calendar above for exact timing.
What planting zone is Douglas County, MN?
Douglas County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is May 3 and first fall frost is October 4.
Your Douglas County Garden Planner — Free
A 24-page printable planner built for Douglas 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.