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When to Plant Radish in Kankakee County, IL

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.

Kankakee County, Illinois is in USDA Zone 5a. The average last spring frost is April 20 and the first fall frost is October 14, giving you a growing season of approximately 177 days.

At an elevation of 1,113 feet, Kankakee County receives approximately 33.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Radish during the growing season.

Kankakee County, IL (Zone 5a) Moderate season
177 days
Last Spring Frost April 20
177 growing days
First Fall Frost October 14

Kankakee County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (126 days to spare)
Transplant: Apr 15 🍅 Harvest: May 13 – Jun 3
Recommended (50%) ✓ Fits season (128 days to spare)
Transplant: Apr 20 🍅 Harvest: May 18 – Jun 8
Safe Start (90%) ✓ Fits season (123 days to spare)
Transplant: May 9 🍅 Harvest: Jun 6 – Jun 27

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
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 319 gal / 100 sq ft
Radish needs ~392 GDD — county provides 2,433 GDD Excellent fit

Radish Planting Timeline โ€” Kankakee County, IL

Radish Planting Calendar

Activity When Date Range
Direct Sow April 6 Apr 6 โ€“ Apr 27
Fall Sowing August 5 Aug 5 โ€“ Aug 19
Harvest May 4 May 4 โ€“ May 25

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Direct Sow
May Harvest
June โ€”
July โ€”
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

22โ€“35 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5a

Growing Season

177 days

Growing Tips for Kankakee 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 Kankakee County, IL?

Kankakee County is in Zone 5a with an average last frost of April 20. Plan your Radish planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Kankakee County, IL?

Kankakee County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 20 and first fall frost is October 14.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Kankakee County gardeners in Zone 5a 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 Kankakee County, IL. Local conditions may vary. Last updated: April 2026.