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When to Plant Horseradish in Sherman County, OR

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.

Sherman County, Oregon is in USDA Zone 6a. The average last spring frost is April 14 and the first fall frost is October 17, giving you a growing season of approximately 186 days.

At an elevation of 862 feet, Sherman County receives approximately 15 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89ยฐF, providing good warmth for Horseradish during the growing season. With low rainfall, drip irrigation is essential for growing Horseradish successfully. Mulch heavily to conserve soil moisture.

Sherman County, OR (Zone 6a) Moderate season
186 days
Last Spring Frost April 14
186 growing days
First Fall Frost October 17

Sherman County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 21 🍅 Harvest: Aug 25 – Nov 3
Recommended (50%) ✗ May not fit
Transplant: Apr 28 🍅 Harvest: Sep 1 – Nov 10
Safe Start (90%) ✗ May not fit
Transplant: May 16 🍅 Harvest: Sep 19 – Nov 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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.3″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 1,095 gal / 100 sq ft
Horseradish needs ~2,512 GDD — county provides 3,115 GDD Good fit

Horseradish Planting Timeline โ€” Sherman County, OR

Horseradish Planting Calendar

Activity When Date Range
Transplant Outdoors April 28 Apr 28 โ€“ May 12
Harvest September 1 Sep 1 โ€“ Nov 10

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Transplant Outdoors
May Transplant Outdoors
June โ€”
July โ€”
August โ€”
September Harvest
October Harvest
November Harvest
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 6a

Growing Season

186 days

Growing Tips for Sherman 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 Sherman County, OR?

Sherman County is in Zone 6a with an average last frost of April 14. Plan your Horseradish planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Sherman County, OR?

Sherman County, Oregon is in USDA Hardiness Zone 6a. The average last spring frost is April 14 and first fall frost is October 17.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Sherman County gardeners in Zone 6a 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 Sherman County, OR. Local conditions may vary. Last updated: April 2026.