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When to Plant Radish in Decatur County, IN

Decatur County, Indiana Zone 6b May

Your May planting checklist for Decatur County, Indiana

May is a pivotal month for Decatur County, Indiana gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 10
Avg. first frost October 20
Soil temp (4") 65°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Pick radish

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

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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.

Decatur County, Indiana is in USDA Zone 6b. The average last spring frost is April 10 and the first fall frost is October 20, giving you a growing season of approximately 193 days.

At an elevation of 985 feet, Decatur County receives approximately 32.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Radish during the growing season.

Decatur County, IN (Zone 6b) Moderate season
193 days
Last Spring Frost April 10
193 growing days
First Fall Frost October 20

Decatur County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (144 days to spare)
Transplant: Apr 7 🍅 Harvest: May 5 – May 26
Recommended (50%) ✓ Fits season (144 days to spare)
Transplant: Apr 10 🍅 Harvest: May 8 – May 29
Safe Start (90%) ✓ Fits season (136 days to spare)
Transplant: Apr 29 🍅 Harvest: May 27 – Jun 17

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 Decatur County

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

Soil pH

Your soil pH (6.2–7.1) overlaps with Radish's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Decatur 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 (4.3%) — 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

11
successive plantings in your 193-day season

Sow every 2.4 weeks. Last sowing by Sep 15 to harvest before frost.

For a dedicated fall crop, sow by Aug 11.

Plant 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 1.5" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.2" 2.8" 0" ✅ Rainfall sufficient
May 2.2" 4.3" 0" ✅ Rainfall sufficient
Jun 2.2" 3.6" 0" ✅ Rainfall sufficient
Jul 2.2" 3.8" 0" ✅ Rainfall sufficient
Aug 2.2" 3.5" 0" ✅ Rainfall sufficient
Sep 2.2" 3.1" 0" ✅ Rainfall sufficient
Oct 2.2" 2.4" 0" ✅ Rainfall sufficient
Nov 2.2" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Decatur 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 ~499 GDD — county provides 3,377 GDD Excellent fit

Radish Planting Timeline — Decatur County, IN

Radish Planting Calendar

Activity When Date Range
Direct Sow March 27 Mar 27 – Apr 17
Harvest April 24 Apr 24 – May 15
Fall Sowing August 11 Aug 11 – Aug 25

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 6b

📆 Growing Season

193 days in Decatur County

Growing Tips for Radish in Decatur County

Direct sow Radish outdoors after April 10 in Decatur County when soil has warmed and frost danger has passed.

Your generous 193.0-day season in Decatur 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 Decatur County, IN?

Decatur County is in Zone 6b with an average last frost of April 10. Plan your Radish planting based on this frost date — see the calendar above for exact timing.

What planting zone is Decatur County, IN?

Decatur County, Indiana is in USDA Hardiness Zone 6b. The average last spring frost is April 10 and first fall frost is October 20.

🌱

Your Decatur County Garden Planner — Free

A 24-page printable planner built for Decatur County (Zone 6b). 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 Decatur 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.