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When to Plant Horseradish in Winnebago 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.

Winnebago County, Wisconsin is in USDA Zone 4b. The average last spring frost is April 30 and the first fall frost is October 12, giving you a growing season of approximately 165 days.

At an elevation of 608 feet, Winnebago County receives approximately 38.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Horseradish to ensure they mature before fall.

Winnebago County, WI (Zone 4b) Moderate season
165 days
Last Spring Frost April 30
165 growing days
First Fall Frost October 12

Winnebago County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (2 days to spare)
Transplant: May 9 🍅 Harvest: Sep 12 – Oct 3
Recommended (50%) ✓ Fits season (4 days to spare)
Transplant: May 14 🍅 Harvest: Sep 17 – Oct 8
Safe Start (90%) ✓ Fits season (4 days to spare)
Transplant: May 29 🍅 Harvest: Oct 2 – Oct 23

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 26 gal / 100 sq ft
Horseradish needs ~1,725 GDD — county provides 1,897 GDD Good fit

Horseradish Planting Timeline โ€” Winnebago County, WI

Horseradish Planting Calendar

Activity When Date Range
Transplant Outdoors May 14 May 14 โ€“ May 28
Harvest September 17 Sep 17 โ€“ Oct 8

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 โ€”
July โ€”
August โ€”
September Harvest
October Harvest
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

120โ€“180 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 4b

Growing Season

165 days

Growing Tips for Winnebago County

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

Level Up Your Garden

Frequently Asked Questions

When should I plant Horseradish in Winnebago County, WI?

Winnebago County is in Zone 4b with an average last frost of April 30. Plan your Horseradish planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Winnebago County, WI?

Winnebago County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is April 30 and first fall frost is October 12.

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Plan Your Garden with Confidence

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

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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 Winnebago County, WI. Local conditions may vary. Last updated: April 2026.