Blog

When to Plant Horseradish in Robertson County, TX

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.

Robertson County, Texas is in USDA Zone 8a. The average last spring frost is March 7 and the first fall frost is November 16, giving you a growing season of approximately 254 days.

At an elevation of 85 feet, Robertson County receives approximately 61.1 inches of rainfall annually with predominantly clay soil. Summer highs average 93ยฐF, providing good warmth for Horseradish during the growing season. Clay soil retains moisture well for Horseradish, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Horseradish root diseases.

Robertson County, TX (Zone 8a) Long season
254 days
Last Spring Frost March 7
254 growing days
First Fall Frost November 16

Robertson County Soil Profile

Soil Type

Clay

Soil pH

6.8-8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (46 days to spare)
Transplant: Mar 14 🍅 Harvest: Jul 18 – Sep 26
Recommended (50%) ✓ Fits season (44 days to spare)
Transplant: Mar 21 🍅 Harvest: Jul 25 – Oct 3
Safe Start (90%) ✓ Fits season (38 days to spare)
Transplant: Apr 21 🍅 Harvest: Aug 25 – Nov 3

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 Robertson County

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

Soil pH

Your soil pH (6.8โ€“8.0) overlaps with Horseradish's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

Heavy clay soil (45% clay) in Robertson County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.

Organic Matter

Organic matter is moderate (3.4%). 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
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” 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 โ€” 1.4" 0" โ„๏ธ Dormant
Feb โ€” 2.2" 0" โ„๏ธ Dormant
Mar 4.3" 4.3" 0" โœ… Rainfall sufficient
Apr 4.3" 5.6" 0" โœ… Rainfall sufficient
May 4.3" 10" 0" โœ… Rainfall sufficient
Jun 4.3" 8.4" 0" โœ… Rainfall sufficient
Jul 4.3" 8.3" 0" โœ… Rainfall sufficient
Aug 4.3" 8.2" 0" โœ… Rainfall sufficient
Sep 4.3" 5.2" 0" โœ… Rainfall sufficient
Oct 4.3" 3.7" 0.6" ๐Ÿ’ง Light watering
Nov 4.3" 2.3" 2" ๐Ÿ’ง Light watering
Dec โ€” 1.6" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Nov in Robertson County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 5,016 GDD Excellent fit

Horseradish Planting Timeline โ€” Robertson County, TX

Horseradish Planting Calendar

Activity When Date Range
Transplant Outdoors March 21 Mar 21 โ€“ Apr 4
Harvest July 25 Jul 25 โ€“ Oct 3

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

120โ€“180 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 8a

๐Ÿ“† Growing Season

254 days in Robertson County

Growing Tips for Horseradish in Robertson County

Direct sow Horseradish outdoors after March 07 in Robertson County when soil has warmed and frost danger has passed.

With Robertson County's clay soil (45% clay), work in 3-4 inches of compost before planting Horseradish. Avoid tilling when soil is wet to prevent compaction.

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 Robertson County, TX?

Robertson County is in Zone 8a with an average last frost of March 7. Plan your Horseradish planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Robertson County, TX?

Robertson County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 7 and first fall frost is November 16.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Robertson County gardeners in Zone 8a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Robertson County, TX. Local conditions may vary. Last updated: April 2026.