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When to Plant Kohlrabi in Harrison County, OH

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.

Harrison County, Ohio is in USDA Zone 5b. The average last spring frost is April 26 and the first fall frost is October 25, giving you a growing season of approximately 182 days.

At an elevation of 1,138 feet, Harrison County receives approximately 38.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Kohlrabi during the growing season.

Harrison County, OH (Zone 5b) Moderate season
182 days
Last Spring Frost April 26
182 growing days
First Fall Frost October 25

Harrison County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (98 days to spare)
Start indoors: Mar 15 Transplant: Apr 19 🍅 Harvest: Jun 7 – Jul 12
Recommended (50%) ✓ Fits season (98 days to spare)
Start indoors: Mar 22 Transplant: Apr 26 🍅 Harvest: Jun 14 – Jul 19
Safe Start (90%) ✓ Fits season (94 days to spare)
Start indoors: Apr 9 Transplant: May 14 🍅 Harvest: Jul 2 – Aug 6

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 Harrison County

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

Soil pH

Your soil pH (6.1โ€“7.2) is within Kohlrabi's preferred range (6.0โ€“7.5).

Soil Texture

The silt loam soil in Harrison County is excellent for Kohlrabi โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.8%) โ€” Kohlrabi will thrive.

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

4
successive plantings in your 182-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
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 โ€” 1.6" 0" โ„๏ธ Dormant
Feb โ€” 1.7" 0" โ„๏ธ Dormant
Mar โ€” 3" 0" โ„๏ธ Dormant
Apr 3" 3.4" 0" โœ… Rainfall sufficient
May 3" 5.1" 0" โœ… Rainfall sufficient
Jun 3" 4.9" 0" โœ… Rainfall sufficient
Jul 3" 3.9" 0" โœ… Rainfall sufficient
Aug 3" 3.5" 0" โœ… Rainfall sufficient
Sep 3" 3.3" 0" โœ… Rainfall sufficient
Oct 3" 3.2" 0" โœ… Rainfall sufficient
Nov โ€” 2.8" 0" โ„๏ธ Dormant
Dec โ€” 2.4" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Harrison County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~756 GDD — county provides 2,502 GDD Excellent fit

Kohlrabi Planting Timeline โ€” Harrison County, OH

Kohlrabi Planting Calendar

Activity When Date Range
Start Indoors March 22 Mar 22 โ€“ Apr 5
Transplant Outdoors April 26 Apr 26 โ€“ May 10
Direct Sow April 12 Apr 12 โ€“ May 3
Harvest June 14 Jun 14 โ€“ Jul 19
Fall Sowing August 16 Aug 16 โ€“ Aug 30

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.7"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

45โ€“65 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

182 days in Harrison County

Growing Tips for Kohlrabi in Harrison County

Direct sow Kohlrabi outdoors after April 26 in Harrison County when soil has warmed and frost danger has passed.

Your generous 182.0-day season in Harrison 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 Harrison County, OH?

Harrison County is in Zone 5b with an average last frost of April 26. Plan your Kohlrabi planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Harrison County, OH?

Harrison County, Ohio is in USDA Hardiness Zone 5b. The average last spring frost is April 26 and first fall frost is October 25.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Harrison County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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