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When to plant Radish in Boone County, IL

The best window to plant Radish in Boone County, is April 9–April 30, when soil warms to 50°F. Last frost typically hits April 23; first frost October 16. A second sowing from August 7 to August 21 extends the harvest into fall.

When to Plant Radish in Boone 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.

Boone County, Illinois is in USDA Zone 5b. The average last spring frost is April 23 and the first fall frost is October 16, giving you a growing season of approximately 176 days.

At an elevation of 512 feet, Boone County receives approximately 39.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Radish to ensure they mature before fall.

Boone County, IL (Zone 5b) Moderate season
176 days
Last Spring Frost April 23
176 growing days
First Fall Frost October 16

Boone County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.8

Drainage

Well Drained

Monthly Watering Guide for Radish

Radish needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Radish Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 4.3" 3.4" 0.9" 💧 Light watering
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 5.7" 0" ✅ Rainfall sufficient
Jul 4.3" 4.9" 0" ✅ Rainfall sufficient
Aug 4.3" 3.8" 0.5" 💧 Light watering
Sep 4.3" 3.5" 0.8" 💧 Light watering
Oct 4.3" 3.5" 0.8" 💧 Light watering
Nov 2.9" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Boone County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Radish Planting Timeline — Boone County, IL

Radish Planting Calendar

Activity When Date Range
Direct Sow April 9 Apr 9 – Apr 30
Harvest May 7 May 7 – May 28
Fall Sowing August 7 Aug 7 – Aug 21

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

22–35 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 5b

📆 Growing Season

176 days in Boone County

Growing Tips for Boone 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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Radish in Boone County, IL?

Boone County is in Zone 5b with an average last frost of April 23. Plan your Radish planting based on this frost date — see the calendar above for exact timing.

What planting zone is Boone County, IL?

Boone County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 23 and first fall frost is October 16.

When should I plant Radish in Boone County, IL?

In Boone County, IL, plant Radish after the last frost (around April 23) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is Boone County, IL for Radish?

Boone County sits in USDA Zone 5b. Radish grows reliably in zones 2a through 11b, so it's a good fit here.

Can Radish grow in Boone County's climate?

Yes — Radish grows well in Boone County's temperate climate. Boone County averages a 176-day frost-free season, with last frost around April 23 and first frost around October 16.

🌱

Your Boone County Garden Planner — Free

A 22-page printable planner built for Boone County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Boone County, IL. Local conditions may vary. Last updated: July 2026.

Sources & credits

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