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Horseradish: How to Plant, Grow, and Harvest Horseradish | The Old Farmer's Almanac

Horseradish

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Kuttelvaserova Stuchelova/Shutterstock
Botanical Name
Armoracia rusticana
Plant Type
Sun Exposure
Hardiness Zone

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How to Plant, Grow, and Harvest Horseradish

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Try growing horseradish, that beloved spicy condiment! A cold-hardy perennial, horseradish can be planted in late fall or early spring. Learn how to plant, grow, and harvest horseradish root in your garden.

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

About Horseradish

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.

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. 

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. 

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 cabbageworms 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.

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 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. 

Gardening Products

Wit and Wisdom

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.

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.”

Pests/Diseases
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
Cooking Notes

Preparing Horseradish for Use as a Condiment

Peel the root and finely grate it, or cut it into cubes and place the horseradish cubes into a blender. Add one or two ice cubes and grind the horseradish until smooth. (Make sure you do this in a well-ventilated room and use eye and nose protection. The smell will be quite pungent.)

Add 1 to 2 tablespoons of white vinegar and a few pinches of salt immediately for mild horseradish. For hot and spicy horseradish, wait 3 minutes before adding 1 to 2 tablespoons of white vinegar and a few pinches of salt.

Homemade Organic Horseradish Sauce in a Bowl
Horseradish sauce is a delicious way to enjoy your horseradish harvest.
Photo Credit: Brent Hofacker/Shutterstock

About The Author

Margaret Boyles

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

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