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When to Plant Horseradish in Monroe County, WI

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.

Monroe County, Wisconsin is in USDA Zone 4b. The average last spring frost is May 9 and the first fall frost is October 3, giving you a growing season of approximately 147 days.

At an elevation of 1,164 feet, Monroe County receives approximately 36.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80ยฐF, so choose short-season varieties of Horseradish to ensure they mature before fall.

Monroe County, WI (Zone 4b) Short season
147 days
Last Spring Frost May 9
147 growing days
First Fall Frost October 3

Monroe County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 14 🍅 Harvest: Sep 17 – Oct 8
Recommended (50%) ✗ May not fit
Transplant: May 23 🍅 Harvest: Sep 26 – Oct 17
Safe Start (90%) ✗ May not fit
Transplant: Jun 3 🍅 Harvest: Oct 7 – Oct 28

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 Monroe County

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

Soil pH

Your soil pH (6.2โ€“7.3) is within Horseradish's preferred range (6.0โ€“7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.8%) โ€” Horseradish will thrive.

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
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 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 โ€” 1.6" 0" โ„๏ธ Dormant
Feb โ€” 1.4" 0" โ„๏ธ Dormant
Mar โ€” 2.2" 0" โ„๏ธ Dormant
Apr โ€” 3.5" 0" โ„๏ธ Dormant
May 4.3" 3.8" 0.5" ๐Ÿ’ง Light watering
Jun 4.3" 4.4" 0" โœ… Rainfall sufficient
Jul 4.3" 4.4" 0" โœ… Rainfall sufficient
Aug 4.3" 4.3" 0" โœ… Rainfall sufficient
Sep 4.3" 3.3" 1" ๐Ÿ’ง Light watering
Oct 4.3" 2.7" 1.6" ๐Ÿ’ง Light watering
Nov โ€” 2.7" 0" โ„๏ธ Dormant
Dec โ€” 1.9" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in Monroe County). Supplement amounts are based on average rainfall โ€” 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" 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.

Horseradish needs ~1,500 GDD — county provides 1,470 GDD Tight fit

Horseradish Planting Timeline โ€” Monroe County, WI

Horseradish Planting Calendar

Activity When Date Range
Transplant Outdoors May 23 May 23 โ€“ Jun 6
Harvest September 26 Sep 26 โ€“ Oct 17

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

120โ€“180 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 4b

๐Ÿ“† Growing Season

147 days in Monroe County

Growing Tips for Horseradish in Monroe County

Direct sow Horseradish outdoors after May 09 in Monroe County when soil has warmed and frost danger has passed.

Your 147.0-day growing season in Monroe 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 Monroe County, WI?

Monroe County is in Zone 4b with an average last frost of May 9. Plan your Horseradish planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Monroe County, WI?

Monroe County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 9 and first fall frost is October 3.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Monroe 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 Monroe County, WI. Local conditions may vary. Last updated: April 2026.