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When to Plant Potatoes in Johnson County, KS

Potatoes are a versatile staple crop that produces tubers underground. They come in hundreds of varieties with varying colors, textures, and maturity dates.

Johnson County, Kansas is in USDA Zone 6a. The average last spring frost is April 8 and the first fall frost is October 26, giving you a growing season of approximately 201 days.

At an elevation of 768 feet, Johnson County receives approximately 27.6 inches of rainfall annually with predominantly loam soil. Summer highs average 87ยฐF, providing good warmth for Potatoes during the growing season.

Johnson County, KS (Zone 6a) Long season
201 days
Last Spring Frost April 8
201 growing days
First Fall Frost October 26

Johnson County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (47 days to spare)
Start indoors: Feb 7 Transplant: Apr 18 🍅 Harvest: Jun 27 – Sep 5
Recommended (50%) ✓ Fits season (47 days to spare)
Start indoors: Feb 11 Transplant: Apr 22 🍅 Harvest: Jul 1 – Sep 9
Safe Start (90%) ✓ Fits season (51 days to spare)
Start indoors: Feb 26 Transplant: May 7 🍅 Harvest: Jul 16 – Sep 24

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 909 gal / 100 sq ft
Drought risk

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

Potatoes needs ~1,449 GDD — county provides 3,065 GDD Excellent fit

Potatoes Planting Timeline โ€” Johnson County, KS

Potatoes Planting Calendar

Activity When Date Range
Start Indoors February 11 Feb 11 โ€“ Feb 25
Transplant Outdoors April 22 Apr 22 โ€“ May 6
Direct Sow April 15 Apr 15 โ€“ May 6
Harvest July 1 Jul 1 โ€“ Sep 9

Plant 1" deep ยท 15" apart ยท Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

70โ€“120 days

Soil pH

5 โ€“ 6.5

USDA Zone

Zone 6a

Growing Season

201 days

Growing Tips for Johnson County

Plant seed potatoes (not grocery store potatoes) 4 inches deep in spring. Hill soil around stems as plants grow to prevent greening. Stop watering when plants die back.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Cucumber
  • Squash Summer

Level Up Your Garden

Frequently Asked Questions

When should I plant Potatoes in Johnson County, KS?

Johnson County is in Zone 6a with an average last frost of April 8. Plan your Potatoes planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Johnson County, KS?

Johnson County, Kansas is in USDA Hardiness Zone 6a. The average last spring frost is April 8 and first fall frost is October 26.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Johnson County gardeners in Zone 6a 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 Johnson County, KS. Local conditions may vary. Last updated: April 2026.