When to Plant Kohlrabi in Coles County, IL
Your May planting checklist for Coles County, Illinois
May is a pivotal month for Coles County, Illinois gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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Get kohlrabi seeds going inside
Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.
Looking ahead to 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.
Coles County, Illinois is in USDA Zone 6a. The average last spring frost is April 14 and the first fall frost is October 17, giving you a growing season of approximately 186 days.
At an elevation of 779 feet, Coles County receives approximately 34.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Kohlrabi during the growing season.
Coles County Soil Profile
Soil Type
Silt Loam
Soil pH
6-7.2
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 Coles County
How your county's soil matches Kohlrabi's growing requirements.
Soil pH
Your soil pH (6.0–7.2) is within Kohlrabi's preferred range (6.0–7.5).
Soil Texture
The silt loam soil in Coles County is excellent for Kohlrabi — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.1%) — 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 13 to harvest before frost.
For a dedicated fall crop, sow by Aug 08.
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 | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.4" | 0" | ❄️ Dormant |
| Apr | 3" | 3.8" | 0" | ✅ Rainfall sufficient |
| May | 3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jun | 3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Jul | 3" | 3.6" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 3.2" | 0" | ✅ Rainfall sufficient |
| Sep | 3" | 2.9" | 0.1" | 💧 Light watering |
| Oct | 3" | 2.8" | 0.2" | 💧 Light watering |
| Nov | — | 2.5" | 0" | ❄️ Dormant |
| Dec | — | 1.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Coles 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 — Coles County, IL
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 8 | Aug 8 – Aug 22 |
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 · Natural rainfall sufficient
📅 Days to Maturity
45–65 days
🧪 Soil pH
Needs 6–7.5 · Your soil: ideal
🗺️ USDA Zone
Zone 6a
📆 Growing Season
186 days in Coles County
Growing Tips for Kohlrabi in Coles County
Direct sow Kohlrabi outdoors after April 14 in Coles County when soil has warmed and frost danger has passed.
Your generous 186.0-day season in Coles 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 Coles County, IL?
Coles County is in Zone 6a 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 Coles County, IL?
Coles County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 14 and first fall frost is October 17.
Your Coles County Garden Planner — Free
A 24-page printable planner built for Coles County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.