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When to Plant Radish in Jasper 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.

Jasper County, Illinois is in USDA Zone 6a. The average last spring frost is April 13 and the first fall frost is October 20, giving you a growing season of approximately 190 days.

At an elevation of 1,384 feet, Jasper County receives approximately 35 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91ยฐF, providing good warmth for Radish during the growing season.

Jasper County, IL (Zone 6a) Moderate season
190 days
Last Spring Frost April 13
190 growing days
First Fall Frost October 20

Jasper County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (141 days to spare)
Transplant: Apr 7 🍅 Harvest: May 5 – May 26
Recommended (50%) ✓ Fits season (141 days to spare)
Transplant: Apr 13 🍅 Harvest: May 11 – Jun 1
Safe Start (90%) ✓ Fits season (138 days to spare)
Transplant: Apr 27 🍅 Harvest: May 25 – Jun 15

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
0.3″/week
Watering frequency Only during dry spells
Season total 459 gal / 100 sq ft
Drought risk

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

Radish needs ~520 GDD — county provides 3,467 GDD Excellent fit

Radish Planting Timeline โ€” Jasper County, IL

Radish Planting Calendar

Activity When Date Range
Direct Sow March 30 Mar 30 โ€“ Apr 20
Fall Sowing August 11 Aug 11 โ€“ Aug 25
Harvest April 27 Apr 27 โ€“ May 18

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 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 6a

Growing Season

190 days

Growing Tips for Jasper 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 Jasper County, IL?

Jasper County is in Zone 6a with an average last frost of April 13. Plan your Radish planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Jasper County, IL?

Jasper County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 13 and first fall frost is October 20.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Jasper 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 Jasper County, IL. Local conditions may vary. Last updated: April 2026.