For daily wit & wisdom, get the Almanac newsletter.

How to Grow Horseradish: Plant, Grow, and Harvest This Spicy Root

horseradish root after it was harvested in the garden
Image Credit:
Kuttelvaserova Stuchelova/Shutterstock
Botanical Name
Armoracia rusticana
Grown as
Perennial
USDA Zones
3a
3b
4a
4b
5a
5b
6a
6b
7a
7b
8a
8b
9a
Toxicity
Non-toxic
Sun Exposure
Full Sun
Water Needs
Moderate
Height
1–3 feet
Spread
1–3 feet
Soil pH
Neutral
Bloom Time
Summer
Flower Color
White
Yellow
Special Features
Container-Friendly
Low Maintenance
Deer-resistant
Rabbit-resistant
Resilience
Cold Hardy
Heat-Tolerant
Plant Type
Vegetables
Written By: Margaret Boyles Contributor

Want to bring some bold flavor to your backyard? Horseradish is the spicy secret weapon your garden didn’t know it needed! This cold-loving perennial grows underground but packs a punch above its weight. 

Plant it once in early spring, and by fall, you’ll be digging up a fiery root perfect for homemade sauces, zesty relishes, or a nose-tingling roast beef companion. Let’s dig into how to grow horseradish the right way.

Horseradish has a long growing season, and you can’t start using it until one year after planting. Also, this root must grow in a climate where the fall and winter are fairly cold. It’s adaptable and tough, but providing the proper growing conditions will produce the biggest, sweetest, and most flavorful roots.

Horseradish is a member of the mustard family. This hardy perennial grows a fleshy taproot that only develops in cold weather, and the best roots have endured several frosts. 

Above ground, horseradish sends up coarse, elongated, emerald green leaves that resemble those of common curly dock. This foliage, which rarely grows more than 2 feet tall, belies the real action underground: In rich soil, the fleshy horseradish taproot can penetrate as deep as 10 feet if left undisturbed for several years and will send out a tangled mass of horizontal secondary roots and rootlets over a diameter of several feet. Just a word of warning: it’s so easy to grow, it might just take over—so plant with purpose!

If severed from the main taproot, any rootlet can give rise to a new plant; this is one way to start a crop. Aspiring horseradish growers can also obtain root cuttings—sometimes called “starts” or “sets”—from seed companies and many local garden supply stores.

Roots are available at farmers’ markets, supermarkets, and mail-order nurseries. 

“The most common problem with horseradish is how to keep it from growing where you don’t want it,” explains Charlotte Welliver, a Master Gardener with PennState Extension. “It can become aggressive if not kept under control. To control the spread, remove the entire root, even the branches, when harvesting. Replant only the number of roots you want for the following season. Whatever you do, don’t till up soil containing horseradish roots because you will risk spreading the plant all over the garden. Almost every little piece of root will sprout where it lies.”

Planting

Plant horseradish in full sun. Horseradish will tolerate partial sun, but yields will not be as good. Soil must be moist, fertile, and loamy, or the roots can’t grow down (similar to carrots).

  • Prepare the soil by tilling 8 to 10 inches down and clearing out any roots or rocks that could impede the horseradish growth. Add a shovel full of compost.
  • Plant roots well away from other garden crops, or follow the practice of savvy gardeners and plant the roots in buried lengths of drainage tile or even a bottomless 5-gallon bucket, to check their spread.
Horseradish bush close-up. Horseradish sheets with rain drops, top view. Large green leaves of horseradish.
Photo credit: Anakumka/Shutterstock

When to Plant Horseradish

  • Plant horseradish sets—small pieces of horseradish root—in early spring, as soon as the soil can be worked, or in fall.
  • Horseradish requires a long growing season, so plan to harvest in the fall (just before a freeze) or in early spring of the following year.

How to Plant Horseradish

Plant horseradish by laying sets or pieces of roots about 18 inches apart and at a 45° angle, in a trench 3 to 4 inches deep. Sets generally come with the lower end sliced off on the diagonal to indicate which end should slant down. With fully horizontal planting, leaves will sprout forth from several points along the length of the set, which is less ideal. Cover over with topsoil after planting. 

You can even grow horseradish in containers!

Growing

  • Fertilize established horseradish in the early spring (the plants make vigorous top growth all summer and then begin storing starch in the root in the fall, which fattens them).
  • Water and weed regularly, but weed carefully when plants are still young.
  • Protect the crops against those pests that commonly attack cabbage family members, like cabbage worms and flea beetles.
  • To prevent the rampant spread of the roots and a buildup of disease organisms, harvest the roots regularly—ideally, every spring or fall—and rotate the bed to a new place occasionally, setting pencil­-size sets broken off the main roots. 

Harvesting

  • Gardeners disagree as to whether spring-dug or late-fall–dug horseradish gives the finest flavor, but most agree that roots dug in summer are unpalatable.
  • We tend to dig our main supply of roots in late October or early November after the foliage is killed by frost and just before the ground freezes.
  • Use a garden fork or shovel and carefully dig up the roots.
  • Following gardening by the moon practices, it is recommended that you dig horseradish during the full Moon for the best flavor.

How to Store Horseradish

  • To prepare for storage, trim foliage down to about 1 inch and clean the roots under running water, scrubbing off any dirt. Allow the roots to dry before storing.
  • Store horseradish in damp sand in the root cellar, in a dark area. Temperatures shouldn’t drop below freezing.
  • For more immediate use, a small supply of roots will keep well in a perforated plastic bag in the refrigerator for up to a couple of months.

Two caveats govern both culinary uses of horseradish:

  • Keep the roots refrigerated to maintain flavor and nutritional value, grating them only as needed, and use them raw.
  • When adding horseradish to hot foods, such as rarebits, sauces, or fondues, stir it in just before serving. 

Pests and Problems

Horseradish Pests and Diseases
Pest/DiseaseTypeSymptomsControl/Prevention
AphidsInsectMisshapen/yellow leaves; distorted flowers; leaf drop; sticky “honeydew” (excretion) on leaves; sooty, black moldKnock off with water spray; apply insecticidal
soap; inspect new plants carefully; use slow- release fertilizers; avoid excess nitrogen; encourage lacewings, lady beetles/bugs, spiders
CabbagewormsInsectLeaves have large, ragged holes or are skeletonized; heads bored; dark green excrement; yellowish eggs laid singly on leaf undersidesHandpick; use row covers; add native plants to invite beneficial insects; grow companion plants (especially thyme); spray Bacillus thuringiensis (Bt)
CutwormsInsectWilting; severed stems of young plants just above or below soil lineHandpick; in spring before planting, cultivate soil to reduce larvae; wrap a 4-inch-wide collar made from cardboard or newspaper around each stem, sinking 2 inches into soil; weed; use row covers; destroy crop residue
Flea beetlesInsectNumerous tiny holes in leavesUse row covers; mulch heavily; add native plants to invite beneficial insects
WirewormsInsectYoung plants severed; stunting/wilting; roots eaten; roots boredTrap by digging 2- to 4-inch-deep holes every 3 to 10 feet, fill with mix of germinating beans/corn/peas or potato sections as bait, cover with soil or a board, in 1 week uncover and kill collected wireworms; sow seeds in warm soil for quick germination; provide good drainage; remove plant debris; rotate crops

Types

  • Common horseradish has broad, crinkled leaves with a superior root quality. However, it is more susceptible to disease.
  • Bohemian horseradish has narrower, smoother leaves than common horseradish and is more disease resistant but has a slightly lower-quality root. 

Wit and Wisdom

  • Horseradish is a popular home remedy for colds and sore throats.
  • Horseradish is a pungent condiment used with meats and fish, and also added to spice up seafood cocktail and ketchup. 

How Horseradish Gets Its Bite

Horseradish gets its characteristic bite from the interaction of two compounds, isolated from each other in separate cells of the plant. Intact roots and leaves have no horseradish-y smell but must be bruised, chopped, shredded, or chewed to combine the two compounds. The finer the grating or grinding, the more pungent and richly flavored the root becomes.

Horseradish Health Benefits

Horseradish roots pack a nutritional wallop that few cultivated plants, and certainly no other root crop, can match. The freshly grated root contains more vitamin C than most common fruit, including oranges. The root is rich in calcium, iron, thiamine, potassium, magnesium, trace minerals, and proteins, yet desirably low in phosphorus and sodium. Horseradish is 20 times richer in calcium than the potato (with skin) and contains nearly four times the vitamin C and three times the iron. This may be why it is one of the ingredients of immunity-boosting fire cider.

There are those who warn that overconsumption of horseradish root will irritate the sensitive lining of the digestive tract; they suggest limiting use to a quarter teaspoon at a time. To them, we offer the remark of a Yankee octogenarian who has grown, processed, and eaten horseradish all of his adult life and takes his daily dose of homemade horseradish sauce straight, by the tablespoonful, accompanied by much lip-smacking, tearing, sniffling, and sweating. “Oh, that’s good stuff,” he exclaims. “Question in my mind is not how I’d get hurt from eatin’ it, but how much worse off I’d be without it.”

Vegetables

About The Author

Margaret Boyles

Margaret Boyles

Contributor

Margaret Boyles is a longtime contributor to The Old Farmer’s Almanac. She wrote for UNH Cooperative Extension, managed NH Outside, and contributes to various media covering environmental and human health issues.

Read more from Margaret Boyles

More Like This

Comments

<span>Rick</span> Tue, 04/28/2020 - 09:48
Be careful where you grow, it spreads.... Would like to know how t get rid of it. Every Spring and Fall I'm digging it up and throwing it out. DO NOT put in compost bin. The remaining shoots come up the next year
<span>Dick S</span> Fri, 10/20/2023 - 14:15
I have the same problem. I've been digging to get rid of it. It is now 6 feet across my garden !! I transplant ed some in pots !but now I can't get it out of my garden !!😛