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When to Plant Radish in Kossuth County, IA

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.

Kossuth County, Iowa is in USDA Zone 4b. The average last spring frost is April 27 and the first fall frost is October 6, giving you a growing season of approximately 162 days.

At an elevation of 1,213 feet, Kossuth County receives approximately 36.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80ยฐF, so choose short-season varieties of Radish to ensure they mature before fall.

Kossuth County, IA (Zone 4b) Moderate season
162 days
Last Spring Frost April 27
162 growing days
First Fall Frost October 6

Kossuth County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (115 days to spare)
Transplant: Apr 21 🍅 Harvest: May 19 – Jun 9
Recommended (50%) ✓ Fits season (113 days to spare)
Transplant: Apr 27 🍅 Harvest: May 25 – Jun 15
Safe Start (90%) ✓ Fits season (115 days to spare)
Transplant: May 11 🍅 Harvest: Jun 8 – Jun 29

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 Kossuth County

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

Soil pH

Your soil pH (6.2โ€“7.0) is within Radish's preferred range (6.0โ€“7.0).

Soil Texture

The silt loam soil in Kossuth County is excellent for Radish โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.9%) โ€” Radish will thrive.

How to Plant Radish

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

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Radish

9
successive plantings in your 162-day season

Sow every 2.4 weeks. Last sowing by Sep 01 to harvest before frost.

For a dedicated fall crop, sow by Jul 14.

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

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 โ€” 1.7" 0" โ„๏ธ Dormant
Feb โ€” 1.4" 0" โ„๏ธ Dormant
Mar โ€” 2.4" 0" โ„๏ธ Dormant
Apr 2.2" 3.8" 0" โœ… Rainfall sufficient
May 2.2" 3.7" 0" โœ… Rainfall sufficient
Jun 2.2" 5.1" 0" โœ… Rainfall sufficient
Jul 2.2" 4.3" 0" โœ… Rainfall sufficient
Aug 2.2" 3.7" 0" โœ… Rainfall sufficient
Sep 2.2" 2.9" 0" โœ… Rainfall sufficient
Oct 2.2" 3.2" 0" โœ… Rainfall sufficient
Nov โ€” 2.5" 0" โ„๏ธ Dormant
Dec โ€” 1.8" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Kossuth County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~285 GDD — county provides 1,620 GDD Excellent fit

Radish Planting Timeline โ€” Kossuth County, IA

Radish Planting Calendar

Activity When Date Range
Direct Sow April 20 Apr 20 โ€“ May 11
Harvest May 18 May 18 โ€“ Jun 8
Fall Sowing July 14 Jul 14 โ€“ Jul 28

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.5"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

22โ€“35 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 4b

๐Ÿ“† Growing Season

162 days in Kossuth County

Growing Tips for Radish in Kossuth County

Direct sow Radish outdoors after April 27 in Kossuth County when soil has warmed and frost danger has passed.

Your generous 162.0-day season in Kossuth 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 Kossuth County, IA?

Kossuth County is in Zone 4b with an average last frost of April 27. Plan your Radish planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Kossuth County, IA?

Kossuth County, Iowa is in USDA Hardiness Zone 4b. The average last spring frost is April 27 and first fall frost is October 6.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Kossuth County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Kossuth County, IA. Local conditions may vary. Last updated: April 2026.