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When to Plant Horseradish in Calloway County, KY

Calloway County, Kentucky Zone 7b May

Calloway County, Kentucky gardeners: here's your May plan

Welcome to May in Zone 7b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 5
Avg. first frost October 29
Soil temp (4") 64°F
Watering Low
Pest pressure Moderate
Daylight 14 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.

Calloway County, Kentucky is in USDA Zone 7b. The average last spring frost is April 5 and the first fall frost is October 29, giving you a growing season of approximately 207 days.

At an elevation of 2,755 feet, Calloway County receives approximately 42 inches of rainfall annually with predominantly silt loam soil. Summer highs average 93°F, providing good warmth for Horseradish during the growing season.

Calloway County, KY (Zone 7b) Long season
207 days
Last Spring Frost April 5
207 growing days
First Fall Frost October 29

Calloway County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 13 🍅 Harvest: Aug 17 – Oct 26
Recommended (50%) ✗ May not fit
Transplant: Apr 19 🍅 Harvest: Aug 23 – Nov 1
Safe Start (90%) ✓ Fits season (0 days to spare)
Transplant: May 1 🍅 Harvest: Sep 4 – Nov 13

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 Calloway County

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

Soil pH

Your soil pH (5.5–6.9) overlaps with Horseradish's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Calloway 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 (2.7%). 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
0.9″/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 3.6" 0" ❄️ Dormant
Feb 3.2" 0" ❄️ Dormant
Mar 3.9" 0" ❄️ Dormant
Apr 4.3" 3.5" 0.8" 💧 Light watering
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 3.9" 0.4" 💧 Light watering
Jul 4.3" 3.7" 0.6" 💧 Light watering
Aug 4.3" 3.5" 0.8" 💧 Light watering
Sep 4.3" 3.6" 0.7" 💧 Light watering
Oct 4.3" 2.7" 1.6" 💧 Light watering
Nov 3.4" 0" ❄️ Dormant
Dec 3.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Calloway 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 ~2,962 GDD — county provides 4,088 GDD Excellent fit

Horseradish Planting Timeline — Calloway County, KY

Horseradish Planting Calendar

Activity When Date Range
Transplant Outdoors April 19 Apr 19 – May 3
Harvest August 23 Aug 23 – Nov 1

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

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: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

207 days in Calloway County

Growing Tips for Horseradish in Calloway County

Direct sow Horseradish outdoors after April 05 in Calloway 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 Calloway County, KY?

Calloway County is in Zone 7b with an average last frost of April 5. Plan your Horseradish planting based on this frost date — see the calendar above for exact timing.

What planting zone is Calloway County, KY?

Calloway County, Kentucky is in USDA Hardiness Zone 7b. The average last spring frost is April 5 and first fall frost is October 29.

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Your Calloway County Garden Planner — Free

A 24-page printable planner built for Calloway County (Zone 7b). 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 Calloway County, KY. 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.