When to Plant Kohlrabi in Walworth County, WI
Walworth County, Wisconsin gardeners: here's your May plan
Here's what deserves your attention in Walworth County, Wisconsin this month. Everything below is tailored to Zone 5b and timed around your local frost dates.
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Start kohlrabi under lights
These need a head start before your last frost (April 26). Sow into cells now so you're ready to transplant in a few weeks.
A few tasks this May that'll pay off in June
- 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.
Walworth County, Wisconsin is in USDA Zone 5b. The average last spring frost is April 26 and the first fall frost is October 13, giving you a growing season of approximately 170 days.
At an elevation of 1,101 feet, Walworth County receives approximately 39.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Kohlrabi during the growing season.
Walworth County Soil Profile
Soil Type
Silt Loam
Soil pH
6.2-6.9
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 Walworth County
How your county's soil matches Kohlrabi's growing requirements.
Soil pH
Your soil pH (6.2–6.9) is within Kohlrabi's preferred range (6.0–7.5).
Soil Texture
The silt loam soil in Walworth 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
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Kohlrabi
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
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 | — | 1.9" | 0" | ❄️ Dormant |
| Feb | — | 1.8" | 0" | ❄️ Dormant |
| Mar | — | 2.5" | 0" | ❄️ Dormant |
| Apr | 3" | 3.8" | 0" | ✅ Rainfall sufficient |
| May | 3" | 4.2" | 0" | ✅ Rainfall sufficient |
| Jun | 3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Jul | 3" | 4.9" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 4.1" | 0" | ✅ Rainfall sufficient |
| Sep | 3" | 4.2" | 0" | ✅ Rainfall sufficient |
| Oct | 3" | 2.9" | 0.1" | 💧 Light watering |
| Nov | — | 2.7" | 0" | ❄️ Dormant |
| Dec | — | 2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Walworth 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 — Walworth County, WI
Kohlrabi Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 22 | Mar 22 – Apr 5 |
| Transplant Outdoors | April 26 | Apr 26 – May 10 |
| Direct Sow | April 12 | Apr 12 – May 3 |
| Harvest | June 14 | Jun 14 – Jul 19 |
| Fall Sowing | August 4 | Aug 4 – Aug 18 |
Plant 0.5" deep · 4" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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 · Natural rainfall sufficient
📅 Days to Maturity
45–65 days
🧪 Soil pH
Needs 6–7.5 · Your soil: ideal
🗺️ USDA Zone
Zone 5b
📆 Growing Season
170 days in Walworth County
Growing Tips for Kohlrabi in Walworth County
Direct sow Kohlrabi outdoors after April 26 in Walworth County when soil has warmed and frost danger has passed.
Your generous 170.0-day season in Walworth 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
Check more plant combinations with our Companion Planting Checker →
Kohlrabi in Other Locations
Frequently Asked Questions
When should I plant Kohlrabi in Walworth County, WI?
Walworth County is in Zone 5b with an average last frost of April 26. Plan your Kohlrabi planting based on this frost date — see the calendar above for exact timing.
What planting zone is Walworth County, WI?
Walworth County, Wisconsin is in USDA Hardiness Zone 5b. The average last spring frost is April 26 and first fall frost is October 13.
Your Walworth County Garden Planner — Free
A 24-page printable planner built for Walworth 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.