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When to Plant Horseradish in Cedar County, IA

Cedar County, Iowa Zone 5a May

May to-do list for Cedar County, Iowa

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Cedar County, Iowa.

Avg. last frost April 17
Avg. first frost October 16
Soil temp (4") 59°F
Watering Low
Pest pressure Low
Daylight 14.4 hrs
  1. Harden off and plant horseradish

    Frost risk is low now in Cedar County, Iowa. If you've been covering beds overnight, you can stop.

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Horseradish is a vigorous perennial grown for its pungent, spicy roots used as a condiment. Once established, it can be difficult to eradicate, so choose its location carefully.

Cedar County, Iowa is in USDA Zone 5a. The average last spring frost is April 17 and the first fall frost is October 16, giving you a growing season of approximately 182 days.

At an elevation of 1,112 feet, Cedar County receives approximately 41 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Horseradish during the growing season.

Cedar County, IA (Zone 5a) Moderate season
182 days
Last Spring Frost April 17
182 growing days
First Fall Frost October 16

Cedar County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 26 🍅 Harvest: Aug 30 – Oct 11
Recommended (50%) ✓ Fits season (0 days to spare)
Transplant: May 1 🍅 Harvest: Sep 4 – Oct 16
Safe Start (90%) ✗ May not fit
Transplant: May 22 🍅 Harvest: Sep 25 – Nov 6

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 Cedar County

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

Soil pH

Your soil pH (5.9–6.9) overlaps with Horseradish's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Horseradish.

Organic Matter

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

How to Plant Horseradish

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 688 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Horseradish

Horseradish needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Horseradish Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 4.3" 3.4" 0.9" 💧 Light watering
May 4.3" 5.1" 0" ✅ Rainfall sufficient
Jun 4.3" 5.3" 0" ✅ Rainfall sufficient
Jul 4.3" 4.9" 0" ✅ Rainfall sufficient
Aug 4.3" 4.7" 0" ✅ Rainfall sufficient
Sep 4.3" 3.5" 0.8" 💧 Light watering
Oct 4.3" 3.2" 1.1" 💧 Light watering
Nov 3" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Cedar County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Horseradish 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.

Horseradish needs ~2,288 GDD — county provides 2,775 GDD Good fit

Horseradish Planting Timeline — Cedar County, IA

Horseradish Planting Calendar

Activity When Date Range
Transplant Outdoors May 1 May 1 – May 15
Harvest September 4 Sep 4 – Oct 16

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July
August
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

120–180 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

182 days in Cedar County

Growing Tips for Horseradish in Cedar County

Direct sow Horseradish outdoors after April 17 in Cedar County when soil has warmed and frost danger has passed.

Your 182.0-day growing season in Cedar County is tight for Horseradish (120.0-180.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Horseradish in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Plant root cuttings at a 45-degree angle in early spring. Harvest roots in late fall for strongest flavor. Contain the plant with barriers or grow in large containers.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Horseradish in Cedar County, IA?

Cedar County is in Zone 5a with an average last frost of April 17. Plan your Horseradish planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cedar County, IA?

Cedar County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 17 and first fall frost is October 16.

🌱

Your Cedar County Garden Planner — Free

A 24-page printable planner built for Cedar County (Zone 5a). 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 Cedar County, IA. Local conditions may vary. Last updated: May 2026.

Sources & credits

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