When to Plant Kohlrabi in Richland County, IL
May to-do list for Richland County, Illinois
Welcome to May in Zone 6b. These are the moves that will have the biggest impact on your growing season.
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Start kohlrabi indoors
Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.
June prep starts now
- 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.
Richland County, Illinois is in USDA Zone 6b. The average last spring frost is April 13 and the first fall frost is October 27, giving you a growing season of approximately 197 days.
At an elevation of 1,135 feet, Richland County receives approximately 39.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Kohlrabi during the growing season.
Richland County Soil Profile
Soil Type
Silt Loam
Soil pH
6.2-7
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 Richland County
How your county's soil matches Kohlrabi's growing requirements.
Soil pH
Your soil pH (6.2–7.0) is within Kohlrabi's preferred range (6.0–7.5).
Soil Texture
The silt loam soil in Richland County is excellent for Kohlrabi — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.0%) — 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 23 to harvest before frost.
For a dedicated fall crop, sow by Aug 18.
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 | — | 1.7" | 0" | ❄️ Dormant |
| Feb | — | 1.6" | 0" | ❄️ Dormant |
| Mar | — | 2.8" | 0" | ❄️ Dormant |
| Apr | 3" | 4.3" | 0" | ✅ Rainfall sufficient |
| May | 3" | 4" | 0" | ✅ Rainfall sufficient |
| Jun | 3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Jul | 3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Sep | 3" | 3.8" | 0" | ✅ Rainfall sufficient |
| Oct | 3" | 3" | 0" | ✅ Rainfall sufficient |
| Nov | — | 3" | 0" | ❄️ Dormant |
| Dec | — | 2.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Richland 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 — Richland County, IL
Kohlrabi Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 9 | Mar 9 – Mar 23 |
| Transplant Outdoors | April 13 | Apr 13 – Apr 27 |
| Direct Sow | March 30 | Mar 30 – Apr 20 |
| Harvest | June 1 | Jun 1 – Jul 6 |
| Fall Sowing | August 18 | Aug 18 – Sep 1 |
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 | Fall Sowing |
| 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 6b
📆 Growing Season
197 days in Richland County
Growing Tips for Kohlrabi in Richland County
Direct sow Kohlrabi outdoors after April 13 in Richland County when soil has warmed and frost danger has passed.
Your generous 197.0-day season in Richland 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 Richland County, IL?
Richland County is in Zone 6b with an average last frost of April 13. Plan your Kohlrabi planting based on this frost date — see the calendar above for exact timing.
What planting zone is Richland County, IL?
Richland County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 13 and first fall frost is October 27.
Your Richland County Garden Planner — Free
A 24-page printable planner built for Richland 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.