When to Plant Kohlrabi in Rusk County, WI
May in Rusk County, Wisconsin — your action list
Welcome to May in Zone 4a. These are the moves that will have the biggest impact on your growing season.
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Get kohlrabi in the ground
Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.
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Scatter kohlrabi into prepared beds
Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.
To set up a strong June, finish these tasks
- Starting indoors: 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.
Rusk County, Wisconsin is in USDA Zone 4a. The average last spring frost is May 16 and the first fall frost is September 28, giving you a growing season of approximately 135 days.
At an elevation of 1,112 feet, Rusk County receives approximately 38.7 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.
Rusk County Soil Profile
Soil Type
Silt Loam
Soil pH
6.1-7
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 Rusk County
How your county's soil matches Kohlrabi's growing requirements.
Soil pH
Your soil pH (6.1–7.0) is within Kohlrabi's preferred range (6.0–7.5).
Soil Texture
The silt loam soil in Rusk County is excellent for Kohlrabi — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.7%) — 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 25 to harvest before frost.
For a dedicated fall crop, sow by Jul 06.
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 | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.8" | 0" | ❄️ Dormant |
| Apr | — | 4" | 0" | ❄️ Dormant |
| May | 3" | 4.6" | 0" | ✅ Rainfall sufficient |
| Jun | 3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jul | 3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 3.9" | 0" | ✅ Rainfall sufficient |
| Sep | 3" | 3.7" | 0" | ✅ Rainfall sufficient |
| Oct | — | 2.8" | 0" | ❄️ Dormant |
| Nov | — | 2.9" | 0" | ❄️ Dormant |
| Dec | — | 2.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Rusk 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 — Rusk County, WI
Kohlrabi Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 4 | Apr 4 – Apr 18 |
| Transplant Outdoors | May 16 | May 16 – May 30 |
| Direct Sow | May 9 | May 9 – May 30 |
| Harvest | July 4 | Jul 4 – Aug 8 |
| Fall Sowing | July 6 | Jul 6 – Jul 20 |
Plant 0.5" deep · 4" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Fall Sowing Harvest |
| August | Harvest |
| 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: ideal
🗺️ USDA Zone
Zone 4a
📆 Growing Season
135 days in Rusk County
Growing Tips for Kohlrabi in Rusk County
Direct sow Kohlrabi outdoors after May 16 in Rusk 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 Rusk County, WI?
Rusk County is in Zone 4a with an average last frost of May 16. Plan your Kohlrabi planting based on this frost date — see the calendar above for exact timing.
What planting zone is Rusk County, WI?
Rusk County, Wisconsin is in USDA Hardiness Zone 4a. The average last spring frost is May 16 and first fall frost is September 28.
Your Rusk County Garden Planner — Free
A 24-page printable planner built for Rusk 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.