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When to Plant Radish in Fremont 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.

Fremont County, Iowa is in USDA Zone 5b. The average last spring frost is April 24 and the first fall frost is October 10, giving you a growing season of approximately 169 days.

At an elevation of 1,032 feet, Fremont County receives approximately 35.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Radish to ensure they mature before fall.

Fremont County, IA (Zone 5b) Moderate season
169 days
Last Spring Frost April 24
169 growing days
First Fall Frost October 10

Fremont County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (116 days to spare)
Transplant: Apr 21 🍅 Harvest: May 19 – Jun 9
Recommended (50%) ✓ Fits season (120 days to spare)
Transplant: Apr 24 🍅 Harvest: May 22 – Jun 12
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 Fremont County

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

Soil pH

Your soil pH (6.2โ€“6.9) is within Radish's preferred range (6.0โ€“7.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Radish.

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

9
successive plantings in your 169-day season

Sow every 2.4 weeks. Last sowing by Sep 05 to harvest before frost.

For a dedicated fall crop, sow by Aug 01.

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
Drought risk

Water stress score is 6/10 โ€” 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 โ€” 1.6" 0" โ„๏ธ Dormant
Feb โ€” 1.4" 0" โ„๏ธ Dormant
Mar โ€” 2.5" 0" โ„๏ธ Dormant
Apr 2.2" 3.8" 0" โœ… Rainfall sufficient
May 2.2" 3.6" 0" โœ… Rainfall sufficient
Jun 2.2" 4.6" 0" โœ… Rainfall sufficient
Jul 2.2" 3.8" 0" โœ… Rainfall sufficient
Aug 2.2" 4.1" 0" โœ… Rainfall sufficient
Sep 2.2" 2.9" 0" โœ… Rainfall sufficient
Oct 2.2" 2.8" 0" โœ… Rainfall sufficient
Nov โ€” 2" 0" โ„๏ธ Dormant
Dec โ€” 1.9" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Fremont 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 ~370 GDD — county provides 2,197 GDD Excellent fit

Radish Planting Timeline โ€” Fremont County, IA

Radish Planting Calendar

Activity When Date Range
Direct Sow April 10 Apr 10 โ€“ May 1
Harvest May 8 May 8 โ€“ May 29
Fall Sowing August 1 Aug 1 โ€“ Aug 15

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 โ€”
July โ€”
August Fall Sowing
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 5b

๐Ÿ“† Growing Season

169 days in Fremont County

Growing Tips for Radish in Fremont County

Direct sow Radish outdoors after April 24 in Fremont County when soil has warmed and frost danger has passed.

Your generous 169.0-day season in Fremont 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 Fremont County, IA?

Fremont County is in Zone 5b with an average last frost of April 24. Plan your Radish planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Fremont County, IA?

Fremont County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 24 and first fall frost is October 10.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Fremont County gardeners in Zone 5b 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 Fremont County, IA. Local conditions may vary. Last updated: April 2026.