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When to Plant Radish in Grant County, IN

Grant County, Indiana Zone 6a April

This month in Grant County, Indiana

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

Avg. last frost April 25
Avg. first frost October 17
Soil temp (4") 46°F
Watering Low
Pest pressure Low
Daylight 13.1 hrs
  1. Outdoor sowing time: radish

    These tolerate cool soil, so you're not gambling by sowing now.

Before May arrives, get these ready
  • First harvests: radish

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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.

Grant County, Indiana is in USDA Zone 6a. The average last spring frost is April 25 and the first fall frost is October 17, giving you a growing season of approximately 175 days.

At an elevation of 682 feet, Grant County receives approximately 40.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Radish during the growing season.

Grant County, IN (Zone 6a) Moderate season
175 days
Last Spring Frost April 25
175 growing days
First Fall Frost October 17
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Grant County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (128 days to spare)
Transplant: Apr 17 🍅 Harvest: May 15 – Jun 5
Recommended (50%) ✓ Fits season (126 days to spare)
Transplant: Apr 25 🍅 Harvest: May 23 – Jun 13
Safe Start (90%) ✓ Fits season (123 days to spare)
Transplant: May 9 🍅 Harvest: Jun 6 – Jun 27

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 Grant County

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

Soil pH

Your soil pH (5.9–6.9) overlaps with Radish's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.0%) — 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 175-day season

Sow every 2.4 weeks. Last sowing by Sep 12 to harvest before frost.

For a dedicated fall crop, sow by Aug 08.

Plant Water Budget

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

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.9" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 2.2" 4.2" 0" ✅ Rainfall sufficient
May 2.2" 4.6" 0" ✅ Rainfall sufficient
Jun 2.2" 5.1" 0" ✅ Rainfall sufficient
Jul 2.2" 4" 0" ✅ Rainfall sufficient
Aug 2.2" 4" 0" ✅ Rainfall sufficient
Sep 2.2" 3.6" 0" ✅ Rainfall sufficient
Oct 2.2" 3.6" 0" ✅ Rainfall sufficient
Nov 2.9" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Grant 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 2,406 GDD Excellent fit

Radish Planting Timeline — Grant 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 8 Aug 8 – Aug 22

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: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

175 days in Grant County

Growing Tips for Radish in Grant County

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

Your generous 175.0-day season in Grant 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 Grant County, IN?

Grant 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 Grant County, IN?

Grant County, Indiana is in USDA Hardiness Zone 6a. The average last spring frost is April 25 and first fall frost is October 17.

🌱

Your Grant County Garden Planner — Free

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

Sources & credits

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