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When to plant Radish in Forsyth, IL

Forsyth gardeners should plant Radish between March 30 and April 20 in spring. With Forsyth's Zone 6a climate (last frost April 13), Radish needs 22–35 days to mature — plant by September 14 for a full harvest. A second sowing from August 10 to August 24 extends the harvest into fall.

When to Plant Radish in Forsyth, IL

Macon County, Illinois Zone 6a June

Your June game plan for Macon County, Illinois

A quick June briefing for Macon County, Illinois gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 13
Avg. first frost October 19
Soil temp (4") 70°F
Watering Low
Pest pressure High
Daylight 14.8 hrs

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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.

Forsyth, Illinois is in USDA Zone 6a. The average last spring frost is April 13 and the first fall frost is October 19, giving you a growing season of approximately 189 days.

At an elevation of 1,064 feet, Macon County receives approximately 31.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Radish during the growing season.

Forsyth, IL (Zone 6a) Moderate season
189 days
Last Spring Frost April 13
189 growing days
First Fall Frost October 19

Forsyth Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.1

Drainage

Well Drained

Radish Planting Risk Windows

Early Start (70% safe) ✓ Fits season (140 days to spare)
Transplant: Apr 7 🍅 Harvest: May 5 – May 26
Recommended (50%) ✓ Fits season (140 days to spare)
Transplant: Apr 13 🍅 Harvest: May 11 – Jun 1
Safe Start (90%) ✓ Fits season (143 days to spare)
Transplant: Apr 24 🍅 Harvest: May 22 – Jun 12

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.

Soil Compatibility in Forsyth

How your county's soil matches Radish's growing requirements.

Soil pH

Your soil pH (6.0–7.1) overlaps with Radish's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Macon County is excellent for Radish — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.3%) — Radish will thrive.

How to Plant Radish

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Radish

10
successive plantings in your 189-day season

Sow every 2.4 weeks. Last sowing by Sep 14 to harvest before frost.

For a dedicated fall crop, sow by Aug 10.

Radish Water Budget

Plant needs
0.5″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Radish

Radish needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Radish Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.2" 2.9" 0" ✅ Rainfall sufficient
May 2.2" 3.1" 0" ✅ Rainfall sufficient
Jun 2.2" 4.1" 0" ✅ Rainfall sufficient
Jul 2.2" 3.5" 0" ✅ Rainfall sufficient
Aug 2.2" 3.5" 0" ✅ Rainfall sufficient
Sep 2.2" 2.9" 0" ✅ Rainfall sufficient
Oct 2.2" 2.3" 0" ✅ Rainfall sufficient
Nov 2.4" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

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

Radish Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Radish needs ~413 GDD — county provides 2,740 GDD Excellent fit

Radish Planting Timeline — Forsyth, IL

Radish Planting Calendar

Activity When Date Range
Direct Sow March 30 Mar 30 – Apr 20
Harvest April 27 Apr 27 – May 18
Fall Sowing August 10 Aug 10 – Aug 24

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

22–35 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

189 days in Macon County

Growing Tips for Radish in Forsyth

Direct sow Radish outdoors after April 13 in Macon County when soil has warmed and frost danger has passed.

Your generous 189.0-day season in Macon County allows multiple plantings of Radish. Sow every 11.0 days for continuous harvest.

Common pests for Radish in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

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 →

When should I plant Radish in Forsyth, IL?

In Forsyth, IL, plant Radish after the last frost (around April 13) and before the first frost (around October 19). Best results when soil holds above 50°F.

What growing zone is Forsyth, IL for Radish?

Forsyth sits in USDA Zone 6a. Radish grows reliably in zones 2a through 11b, so it's a good fit here.

Can Radish grow in Forsyth's climate?

Yes — Radish grows well in Forsyth's temperate climate. Forsyth averages a 189-day frost-free season, with last frost around April 13 and first frost around October 19.

🌱

Your Macon County Garden Planner — Free

A 22-page printable planner built for Macon County (Zone 6a). 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 Macon County, IL. Local conditions may vary. Last updated: June 2026.