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When to Plant Horseradish in Benton County, MO

Benton County, Missouri Zone 6b May

Benton County, Missouri gardeners: here's your May plan

We've pulled the most time-sensitive tasks for Benton County, Missouri this May and put them front and centre. Tackle them in order.

Avg. last frost April 9
Avg. first frost October 25
Soil temp (4") 64°F
Watering Low
Pest pressure Low
Daylight 14.1 hrs

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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.

Benton County, Missouri is in USDA Zone 6b. The average last spring frost is April 9 and the first fall frost is October 25, giving you a growing season of approximately 199 days.

At an elevation of 1,323 feet, Benton County receives approximately 39.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Horseradish during the growing season.

Benton County, MO (Zone 6b) Moderate season
199 days
Last Spring Frost April 9
199 growing days
First Fall Frost October 25
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Benton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 18 🍅 Harvest: Aug 22 – Oct 31
Recommended (50%) ✗ May not fit
Transplant: Apr 23 🍅 Harvest: Aug 27 – Nov 5
Safe Start (90%) ✗ May not fit
Transplant: May 12 🍅 Harvest: Sep 15 – Nov 24

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 Benton County

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

Soil pH

Your soil pH (5.3–6.6) is more acidic than Horseradish prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Benton 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 (3.2%). 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
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 1.5" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 4.3" 4.4" 0" ✅ Rainfall sufficient
May 4.3" 5.1" 0" ✅ Rainfall sufficient
Jun 4.3" 4.3" 0" ✅ Rainfall sufficient
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 3.5" 0.8" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 2.4" 0" ❄️ Dormant
Dec 2.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Benton 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 ~2,625 GDD — county provides 3,482 GDD Excellent fit

Horseradish Planting Timeline — Benton County, MO

Horseradish Planting Calendar

Activity When Date Range
Transplant Outdoors April 23 Apr 23 – May 7
Harvest August 27 Aug 27 – Nov 5

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

120–180 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

199 days in Benton County

Growing Tips for Horseradish in Benton County

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

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 Benton County, MO?

Benton County is in Zone 6b with an average last frost of April 9. Plan your Horseradish planting based on this frost date — see the calendar above for exact timing.

What planting zone is Benton County, MO?

Benton County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 9 and first fall frost is October 25.

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Your Benton County Garden Planner — Free

A 24-page printable planner built for Benton County (Zone 6b). 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 Benton County, MO. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.