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When to Plant Kohlrabi in Warren County, MO

Warren County, Missouri Zone 6b May

Your May game plan for Warren County, Missouri

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Warren County, Missouri.

Avg. last frost April 11
Avg. first frost October 25
Soil temp (4") 62°F
Watering Moderate
Pest pressure Low
Daylight 14.1 hrs
  1. Get kohlrabi seeds going inside

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

  2. Basket week: kohlrabi

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Looking ahead to June
  • First harvests: kohlrabi

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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.

Warren County, Missouri is in USDA Zone 6b. The average last spring frost is April 11 and the first fall frost is October 25, giving you a growing season of approximately 197 days.

At an elevation of 654 feet, Warren County receives approximately 30 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Kohlrabi during the growing season.

Warren County, MO (Zone 6b) Moderate season
197 days
Last Spring Frost April 11
197 growing days
First Fall Frost October 25
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Warren County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (111 days to spare)
Start indoors: Mar 1 Transplant: Apr 5 🍅 Harvest: May 24 – Jun 28
Recommended (50%) ✓ Fits season (113 days to spare)
Start indoors: Mar 7 Transplant: Apr 11 🍅 Harvest: May 30 – Jul 4
Safe Start (90%) ✓ Fits season (112 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: Jun 11 – Jul 16

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 Warren County

How your county's soil matches Kohlrabi's growing requirements.

Soil pH

Your soil pH (5.5–6.5) overlaps with Kohlrabi's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Warren County is excellent for Kohlrabi — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.1%). Annual compost additions will help Kohlrabi.

How to Plant Kohlrabi

0.5"
Planting Depth
4"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Kohlrabi

5
successive plantings in your 197-day season

Sow every 5.1 weeks. Last sowing by Aug 21 to harvest before frost.

For a dedicated fall crop, sow by Aug 16.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.6″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 106 gal / 100 sq ft

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 1.2" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 3" 2.6" 0.4" 💧 Light watering
May 3" 3.2" 0" ✅ Rainfall sufficient
Jun 3" 3.9" 0" ✅ Rainfall sufficient
Jul 3" 3.2" 0" ✅ Rainfall sufficient
Aug 3" 3.6" 0" ✅ Rainfall sufficient
Sep 3" 2.3" 0.7" 💧 Light watering
Oct 3" 2.2" 0.8" 💧 Light watering
Nov 2.3" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Warren 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 needs ~921 GDD — county provides 3,299 GDD Excellent fit

Kohlrabi Planting Timeline — Warren County, MO

Kohlrabi Planting Calendar

Activity When Date Range
Start Indoors March 7 Mar 7 – Mar 21
Transplant Outdoors April 11 Apr 11 – Apr 25
Direct Sow March 28 Mar 28 – Apr 18
Harvest May 30 May 30 – Jul 4
Fall Sowing August 16 Aug 16 – Aug 30

Plant 0.5" deep · 4" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors Direct Sow
April Transplant Outdoors Direct Sow
May Harvest
June Harvest
July Harvest
August Fall Sowing
September
October
November
December
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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

197 days in Warren County

Growing Tips for Kohlrabi in Warren County

Direct sow Kohlrabi outdoors after April 11 in Warren County when soil has warmed and frost danger has passed.

Your generous 197.0-day season in Warren 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

  • Tomatoes
  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Kohlrabi in Warren County, MO?

Warren County is in Zone 6b with an average last frost of April 11. Plan your Kohlrabi planting based on this frost date — see the calendar above for exact timing.

What planting zone is Warren County, MO?

Warren County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 11 and first fall frost is October 25.

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Your Warren County Garden Planner — Free

A 24-page printable planner built for Warren 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.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Warren County, MO. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.