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When to Plant Radish in Allen County, IN

Allen County, Indiana Zone 6a May

Your May game plan for Allen County, Indiana

Each item below is timed to Allen County, Indiana's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 25
Avg. first frost October 21
Soil temp (4") 57°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
  1. Pick radish

    If you can't use it all right away, check the food-preservation section of your planner.

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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.

Allen County, Indiana is in USDA Zone 6a. The average last spring frost is April 25 and the first fall frost is October 21, giving you a growing season of approximately 179 days.

At an elevation of 721 feet, Allen County receives approximately 38.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Radish during the growing season.

Allen County, IN (Zone 6a) Moderate season
179 days
Last Spring Frost April 25
179 growing days
First Fall Frost October 21
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Allen County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (131 days to spare)
Transplant: Apr 16 🍅 Harvest: May 14 – Jun 4
Recommended (50%) ✓ Fits season (130 days to spare)
Transplant: Apr 25 🍅 Harvest: May 23 – Jun 13
Safe Start (90%) ✓ Fits season (128 days to spare)
Transplant: May 7 🍅 Harvest: Jun 4 – Jun 25

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 Allen County

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

Soil pH

Your soil pH (6.0–7.0) is within Radish's preferred range (6.0–7.0).

Soil Texture

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

Drainage

Drainage is adequate for Radish.

Organic Matter

Organic matter is excellent (4.6%) — 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 179-day season

Sow every 2.4 weeks. Last sowing by Sep 16 to harvest before frost.

For a dedicated fall crop, sow by Aug 12.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.9″/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 1.6" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 2.2" 3.4" 0" ✅ Rainfall sufficient
May 2.2" 4" 0" ✅ Rainfall sufficient
Jun 2.2" 4.9" 0" ✅ Rainfall sufficient
Jul 2.2" 4.1" 0" ✅ Rainfall sufficient
Aug 2.2" 4.6" 0" ✅ Rainfall sufficient
Sep 2.2" 3.8" 0" ✅ Rainfall sufficient
Oct 2.2" 2.8" 0" ✅ Rainfall sufficient
Nov 2.9" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Allen 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 ~392 GDD — county provides 2,461 GDD Excellent fit

Radish Planting Timeline — Allen County, IN

Radish Planting Calendar

Activity When Date Range
Direct Sow April 11 Apr 11 – May 2
Harvest May 9 May 9 – May 30
Fall Sowing August 12 Aug 12 – Aug 26

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 6a

📆 Growing Season

179 days in Allen County

Growing Tips for Radish in Allen County

Direct sow Radish outdoors after April 25 in Allen County when soil has warmed and frost danger has passed.

Your generous 179.0-day season in Allen 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 →

Frequently Asked Questions

When should I plant Radish in Allen County, IN?

Allen County is in Zone 6a with an average last frost of April 25. Plan your Radish planting based on this frost date — see the calendar above for exact timing.

What planting zone is Allen County, IN?

Allen County, Indiana is in USDA Hardiness Zone 6a. The average last spring frost is April 25 and first fall frost is October 21.

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Your Allen County Garden Planner — Free

A 24-page printable planner built for Allen 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 Allen County, IN. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.