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When to Plant Horseradish in Canyon County, ID

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.

Canyon County, Idaho is in USDA Zone 6b. The average last spring frost is May 4 and the first fall frost is October 10, giving you a growing season of approximately 159 days.

At an elevation of 4,953 feet, Canyon County receives approximately 13.3 inches of rainfall annually with predominantly loam soil. Summer highs average 87ยฐF, 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.

Canyon County, ID (Zone 6b) Moderate season
159 days
Last Spring Frost May 4
159 growing days
First Fall Frost October 10

Canyon County Soil Profile

Soil Type

Loam

Soil pH

6.2-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 4 🍅 Harvest: Sep 7 – Nov 16
Recommended (50%) ✗ May not fit
Transplant: May 18 🍅 Harvest: Sep 21 – Nov 30
Safe Start (90%) ✓ Fits season (297 days to spare)
Transplant: Jun 20 🍅 Harvest: Oct 24 – Jan 2

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
0.4″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,102 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Horseradish needs ~2,288 GDD — county provides 2,424 GDD Good fit

Horseradish Planting Timeline โ€” Canyon County, ID

Horseradish Planting Calendar

Activity When Date Range
Transplant Outdoors May 18 May 18 โ€“ Jun 1
Harvest September 21 Sep 21 โ€“ Nov 30

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 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 6b

Growing Season

159 days

Growing Tips for Canyon 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 Canyon County, ID?

Canyon County is in Zone 6b with an average last frost of May 4. Plan your Horseradish planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Canyon County, ID?

Canyon County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is May 4 and first fall frost is October 10.

๐ŸŒฑ

Plan Your Garden with Confidence

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