When to Plant Kohlrabi in Jefferson County, KS
May in the garden — Jefferson County, Kansas
Welcome to May in Zone 6b. These are the moves that will have the biggest impact on your growing season.
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Get kohlrabi seeds going inside
You're about 24 weeks out from your last frost — the perfect window to get these germinating indoors.
Get ahead of 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.
Jefferson County, Kansas is in USDA Zone 6b. The average last spring frost is April 14 and the first fall frost is October 24, giving you a growing season of approximately 193 days.
At an elevation of 559 feet, Jefferson County receives approximately 23.8 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Kohlrabi during the growing season.
Jefferson County Soil Profile
Soil Type
Loam
Soil pH
6.7-7.6
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 Jefferson County
How your county's soil matches Kohlrabi's growing requirements.
Soil pH
Your soil pH (6.7–7.6) overlaps with Kohlrabi's range (6.0–7.5), though not a perfect match.
Soil Texture
The loam soil in Jefferson County is excellent for Kohlrabi — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.3%). Annual compost additions will help Kohlrabi.
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 20 to harvest before frost.
For a dedicated fall crop, sow by Aug 15.
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 | — | 0.7" | 0" | ❄️ Dormant |
| Feb | — | 0.7" | 0" | ❄️ Dormant |
| Mar | — | 1.4" | 0" | ❄️ Dormant |
| Apr | 3" | 2.5" | 0.5" | 💧 Light watering |
| May | 3" | 3.3" | 0" | ✅ Rainfall sufficient |
| Jun | 3" | 3.5" | 0" | ✅ Rainfall sufficient |
| Jul | 3" | 3.5" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 2.6" | 0.4" | 💧 Light watering |
| Sep | 3" | 2.5" | 0.5" | 💧 Light watering |
| Oct | 3" | 1.4" | 1.6" | 🚿 Regular watering |
| Nov | — | 0.8" | 0" | ❄️ Dormant |
| Dec | — | 0.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Jefferson 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 — Jefferson County, KS
Kohlrabi Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 10 | Mar 10 – Mar 24 |
| Transplant Outdoors | April 14 | Apr 14 – Apr 28 |
| Direct Sow | March 31 | Mar 31 – Apr 21 |
| Harvest | June 2 | Jun 2 – Jul 7 |
| Fall Sowing | August 15 | Aug 15 – Aug 29 |
Plant 0.5" deep · 4" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| 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: acceptable
🗺️ USDA Zone
Zone 6b
📆 Growing Season
193 days in Jefferson County
Growing Tips for Kohlrabi in Jefferson County
Direct sow Kohlrabi outdoors after April 14 in Jefferson County when soil has warmed and frost danger has passed.
Your generous 193.0-day season in Jefferson 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 Jefferson County, KS?
Jefferson County is in Zone 6b with an average last frost of April 14. Plan your Kohlrabi planting based on this frost date — see the calendar above for exact timing.
What planting zone is Jefferson County, KS?
Jefferson County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 14 and first fall frost is October 24.
Your Jefferson County Garden Planner — Free
A 24-page printable planner built for Jefferson County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.