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When to Plant Kohlrabi in Sumner County, KS

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.

Sumner County, Kansas is in USDA Zone 6b. The average last spring frost is April 11 and the first fall frost is October 26, giving you a growing season of approximately 198 days.

At an elevation of 637 feet, Sumner County receives approximately 29 inches of rainfall annually with predominantly loam soil. Summer highs average 85ยฐF, providing good warmth for Kohlrabi during the growing season.

Sumner County, KS (Zone 6b) Moderate season
198 days
Last Spring Frost April 11
198 growing days
First Fall Frost October 26

Sumner County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (115 days to spare)
Start indoors: Mar 1 Transplant: Apr 5 🍅 Harvest: May 24 – Jun 28
Recommended (50%) ✓ Fits season (114 days to spare)
Start indoors: Mar 7 Transplant: Apr 11 🍅 Harvest: May 30 – Jul 4
Safe Start (90%) ✓ Fits season (117 days to spare)
Start indoors: Mar 21 Transplant: Apr 25 🍅 Harvest: Jun 13 – Jul 18

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 814 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Kohlrabi needs ~756 GDD — county provides 2,722 GDD Excellent fit

Kohlrabi Planting Timeline โ€” Sumner County, KS

Kohlrabi Planting Calendar

Activity When Date Range
Start Indoors March 7 Mar 7 โ€“ Mar 21
Transplant Outdoors April 11 Apr 11 โ€“ Apr 25
Direct Sow March 28 Mar 28 โ€“ Apr 18
Fall Sowing August 17 Aug 17 โ€“ Aug 31
Harvest May 30 May 30 โ€“ Jul 4

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

45โ€“65 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 6b

Growing Season

198 days

Growing Tips for Sumner County

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

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Frequently Asked Questions

When should I plant Kohlrabi in Sumner County, KS?

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

What planting zone is Sumner County, KS?

Sumner County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 11 and first fall frost is October 26.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Sumner County gardeners in Zone 6b organize planting dates, track what's growing, and never miss a planting window.

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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 Sumner County, KS. Local conditions may vary. Last updated: April 2026.