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When to Plant Horseradish in Putnam County, MO

Putnam County, Missouri Zone 5b May

May to-do list for Putnam County, Missouri

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 18
Avg. first frost October 16
Soil temp (4") 58°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Time to transplant horseradish

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

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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.

Putnam County, Missouri is in USDA Zone 5b. The average last spring frost is April 18 and the first fall frost is October 16, giving you a growing season of approximately 181 days.

At an elevation of 1,185 feet, Putnam County receives approximately 40.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Horseradish to ensure they mature before fall.

Putnam County, MO (Zone 5b) Moderate season
181 days
Last Spring Frost April 18
181 growing days
First Fall Frost October 16

Putnam County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 27 🍅 Harvest: Aug 31 – Oct 12
Recommended (50%) ✗ May not fit
Transplant: May 2 🍅 Harvest: Sep 5 – Oct 17
Safe Start (90%) ✗ May not fit
Transplant: May 17 🍅 Harvest: Sep 20 – Nov 1

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 Putnam County

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

Soil pH

Your soil pH (5.6–7.0) overlaps with Horseradish's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Putnam County is excellent for Horseradish — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.1%). 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
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 112 gal / 100 sq ft

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 1.7" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 4.3" 4.1" 0.2" 💧 Light watering
May 4.3" 4.4" 0" ✅ Rainfall sufficient
Jun 4.3" 5.4" 0" ✅ Rainfall sufficient
Jul 4.3" 3.9" 0.4" 💧 Light watering
Aug 4.3" 4.1" 0.2" 💧 Light watering
Sep 4.3" 3.6" 0.7" 💧 Light watering
Oct 4.3" 3.2" 1.1" 💧 Light watering
Nov 2.7" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Putnam 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 ~1,838 GDD — county provides 2,217 GDD Good fit

Horseradish Planting Timeline — Putnam County, MO

Horseradish Planting Calendar

Activity When Date Range
Transplant Outdoors May 2 May 2 – May 16
Harvest September 5 Sep 5 – Oct 17

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

120–180 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

181 days in Putnam County

Growing Tips for Horseradish in Putnam County

Direct sow Horseradish outdoors after April 18 in Putnam County when soil has warmed and frost danger has passed.

Your 181.0-day growing season in Putnam County is tight for Horseradish (120.0-180.0 days to maturity). Start indoors and choose early-maturing varieties.

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 Putnam County, MO?

Putnam County is in Zone 5b with an average last frost of April 18. Plan your Horseradish planting based on this frost date — see the calendar above for exact timing.

What planting zone is Putnam County, MO?

Putnam County, Missouri is in USDA Hardiness Zone 5b. The average last spring frost is April 18 and first fall frost is October 16.

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Your Putnam County Garden Planner — Free

A 24-page printable planner built for Putnam County (Zone 5b). 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 Putnam County, MO. Local conditions may vary. Last updated: May 2026.

Sources & credits

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