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When to Plant Radish in Harper County, KS

Radishes are one of the fastest-growing vegetables, with some varieties ready in under a month. They come in round, elongated, and large winter types.

Harper County, Kansas is in USDA Zone 6b. The average last spring frost is April 9 and the first fall frost is October 27, giving you a growing season of approximately 201 days.

At an elevation of 745 feet, Harper County receives approximately 27.7 inches of rainfall annually with predominantly loam soil. Summer highs average 88ยฐF, providing good warmth for Radish during the growing season.

Harper County, KS (Zone 6b) Long season
201 days
Last Spring Frost April 9
201 growing days
First Fall Frost October 27

Harper County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (154 days to spare)
Transplant: Apr 3 🍅 Harvest: May 1 – May 22
Recommended (50%) ✓ Fits season (152 days to spare)
Transplant: Apr 9 🍅 Harvest: May 7 – May 28
Safe Start (90%) ✓ Fits season (155 days to spare)
Transplant: Apr 22 🍅 Harvest: May 20 – Jun 10

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
0.9″/week
Watering frequency 2-3 times/week
Season total 1,548 gal / 100 sq ft
Drought risk

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

Radish needs ~456 GDD — county provides 3,216 GDD Excellent fit

Radish Planting Timeline โ€” Harper County, KS

Radish Planting Calendar

Activity When Date Range
Direct Sow March 26 Mar 26 โ€“ Apr 16
Fall Sowing August 18 Aug 18 โ€“ Sep 1
Harvest April 23 Apr 23 โ€“ May 14

Plant 0.5" deep ยท 2" apart ยท Rows 6" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

22โ€“35 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 6b

Growing Season

201 days

Growing Tips for Harper County

Direct sow every 1-2 weeks for continuous harvest. Do not transplant. Harvest spring radishes promptly to prevent them from becoming pithy and hot.

Companion Planting

Good Companions

Avoid Planting Near

  • Hyssop

Level Up Your Garden

Frequently Asked Questions

When should I plant Radish in Harper County, KS?

Harper County is in Zone 6b with an average last frost of April 9. Plan your Radish planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Harper County, KS?

Harper County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 9 and first fall frost is October 27.

๐ŸŒฑ

Plan Your Garden with Confidence

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