How to Grow Horseradish

Analysis by Dr. Joseph Mercola Fact Checked

Story at-a-glance -

  • If you love a little (or a lot of) flavor on your sandwiches and other kitchen concoctions, horseradish never fails to please, as the unique flavor imparts its own distinctive rush of heat to tickle your nasal passages
  • Horseradish is quite easy to grow, and as a perennial plant, it comes back year after year, tolerating cold with little trouble and growing well in partial shade for a fall, winter or spring harvest
  • Even fans of the peppery root may be unaware that horseradish has been used as a medicinal herb for helping to clear a stuffy nose, but far beyond that, isothiocyanates are potent against several carcinogens
  • Horseradish tea is sometimes used as a preventive fungicide on fruits and other plants plagued by fungal diseases
  • You can purchase horseradish sauce nearly anywhere, but it can get expensive and worse, be laced with preservatives and sweeteners that are neither necessary nor desirable

You can get a 6-ounce jar of extra hot, "feels like your hair is falling out" Atomic brand horseradish sauce on Amazon for $5.99. If you're a horseradish lover, that might not be a problem, but can you imagine growing your own spicy horseradish roots to produce your own horseradish sauces, saving money and learning the tricks of this easy-to-propagate, fast-growing crop?

Horseradish tolerates nearly every climate, but generally requires full sun or part shade. Starting with "crowns" or roots acquired either by a generous gardening friend, the supermarket or nursery, these are best planted in the spring for harvesting in fall, winter and the following spring. For one household, three plants is usually all you need to rustle up some tantalizingly tasty heat for any number of dishes, or a simple spread for sandwiches.

Although it can be grown from seed, horseradish is usually propagated from a small root piece. With its botanical name Armoracia rusticana, horseradish roots may look a little like skinny parsnips or pale carrots with their tough, leathery skin. But one nick of your hoe on their brown skin reveals not just cream-colored flesh inside, but a nasal-burning sensation that tells you there's something a little hotter going on.

Horseradish is usually made into a sauce that turns potatoes, sandwiches, eggs and roast beef — and that's a very limited list — into a flavor sensation. Patricia Boudier, co-owner of Peaceful Valley Farm & Garden Supply, featured in the above video, explains her own experience with the spicy root:

"I grew up eating horseradish. We put it in our potatoes, we grated it on sandwiches and we made a cream sauce out of it. And if you like a wasabi rush, you need to grow some horseradish."

The unique essence of horseradish is a pleasant addition to kimchi, fermented mustard, flavorful summer rolls, sushi, and bread-and-butter pickles. Wasabi, however, is the Japanese version of a tasty heat in a thick green paste that many people crave, but few people are aware that much of the "wasabi" sold in the U.S. is actually horseradish. Morning Chores explains:

"True wasabi — as in the stuff made from the Wasabia Japonica root — is incredibly hard to find outside of Japan. The plant is also super picky about growing conditions. In fact, to grow it in most areas, you'd need to create the perfect artificial conditions and intensively care for plants for two years before harvesting."1

The Key to the Kick: Two Healing Plant Chemicals

Preparing horseradish for your table isn't much more difficult than shopping for it at the store, bringing it home and twisting off the lid. After harvesting it, simply peel the rough skin and grate the root straight up into whatever dish needs an extra punch of flavor. The key to the kick, it turns out, comes from powerful plant chemicals known as isothiocyanates.

Derived from the hydrolysis of glucosinolates, the sulfur-containing compounds found in horseradish (including glucosinate enzymes that are 10 times more powerful than those in broccoli2), are especially effective in fighting lung and esophageal cancers.3 These gastrointestinal and respiratory tract cancers can be diminished by these phytochemicals, according to Physicians Committee for Responsible Medicine.4

As one study5 notes, isothiocyanates are effective against cancer in three different ways:

  1. They prevent carcinogens from activating
  2. They counteract the toxic effects of activated carcinogens
  3. They fast-track their removal from your body

The Linus Pauling Institute asserts that cruciferous vegetables such as horseradish contain a variety of glucosinolates, each of which forms a different isothiocyanate when hydrolyzed. That hydrolysis is catalyzed by a class of enzymes known as myrosinase (or β-thioglucosidase) which forms several breakdown compounds, including indoles, thiocyanates and isothiocyanates.6

In addition, whether you eat them or are exposed to them in the environment, antioxidant sulforaphane increases enzymes in your liver that help destroy cancer-causing chemicals. It's even been called one of the most powerful anticarcinogens found in food.7 Other areas the compounds in horseradish have been known to be effective against include skin blemishes, gallbladder problems, respiratory problems, headaches, asthma, sciatic nerve pain and more.

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Horseradish to Eat for Fall and Winter Heat

Without adding a lot of adjectives, you could simply say growing horseradish is easy. The root is not only what you eat; it's also what you plant, and they grow deep into the soil like a carrot. Here's one tip that helps explain just how easy: If you don't harvest the entire root, you'll end up with another horseradish plant the following year, as it easily propagates on its own.

In fact, it's so easy you may need to learn a few tricks to keep it from cropping up in flower beds next to it. Leaving a one-and-a-half-foot buffer zone between your horseradish and other plants may be wise; if the rhizomes start popping up in the buffer zone, dig them up and share them with heat-loving friends and neighbors, or start another plant bed.

While you can plant horseradish roots directly into the ground, to prevent the horseradish invasion and make harvesting easier as well, you can use large pots or half-size barrels that hold a minimum of 15 gallons.

Horseradish is very cold hardy; some sources says it grows best in gardening zones 4 through 7, which encompasses roughly the upper three-quarters of the U.S., but others maintain zones 3 and 9 work well, too. The good news is that if you're looking for heat, horseradish thrives where hard freezes are common, as it forces the plants into dormancy. It also becomes more pungent where long, cool growing seasons are the norm, particularly in the fall. Mother Earth News offers a few more tips:

"Growing horseradish is easy in Zones 4 to 7, where established horseradish plants require little care… (It) grows best in moist, silty soils like those found in river bottomland, but enriched clay or sandy loam with a near neutral pH is acceptable. Situate horseradish roots diagonally in the soil, with the slanted end down and the flat end up."8

That said, the above video features Boudier's tips on growing horseradish in gardening Zone 8, which covers a wide horizontal band across the Southern U.S., generally from South Carolina through middle Texas to narrower bands upward to Washington state. This zone's first frost date is December 1, the last frost date is April 1, and temperatures rarely dip below 15 degrees Fahrenheit.

Propagating Horseradish: Tips and Tricks

Because these roots have a tendency to dry out after being harvested, you may want to soak yours in water for a few hours before planting. Fill your pot (or garden plot) with a high-quality potting soil. Place a single root into one pot with the crown at the top (where the leaves will emerge) as horseradish becomes quite large.

Cover the root with about 5 inches of soil, and while you don't want them to get waterlogged, keep them watered well until the plants are about 1 foot high. Don't worry; they grow incredibly fast.

Boudier also recommends adding a high phosphorus-low nitrogen fertilizer (too much nitrogen may produce more leaves than roots) or booster blend to your soil will help augment the root system, but your own compost tea is a recipe that's inexpensive and simple to make. In fact, you can make a compost tea out of the horseradish itself. It's useful as a preventive fungicide that you can spray on fruits and other plants to prevent or treat damaging and unsightly diseases. Off the Grid News reports:

"Horseradish is a potent substance, as anyone who has eaten it can tell you. That spicy flavor indicates a potent cleanser that is an excellent way to prevent fungal infections and particularly, brown rot in apple trees. Process 1 cup of horseradish roots in a blender or food processor and mix with 2 cups of water. Let it sit for 24 hours and strain out the roots. Dilute this liquid with 2 quarts of water.

It is best to use the spray in the early morning or in the evening. Do not spray when it is too hot, or it may burn your plant's leaves. Before trying any spray, you would be wise to test it on one leaf first. Observe the leaf 24 hours later to see if there was an adverse reaction. Only spray the part of the plant that is diseased. Protect yourself while spraying. Some of the ingredients may be irritating to your eyes, nose, or skin."9

When you look at different types of horseradish varieties, the first thing you'll likely notice about the generally long, narrow leaves is that they can vary. Older strains can be as wide as 10 inches across, while "Bohemian" (smooth-leaf) varieties originating in Czechoslovakia, such as Maliner Kren (crinkly), are usually what's used when the plant is grown commercially, and these leaves are narrower.

The Virginia Cooperative Extension10 explains that as horseradish plants grow to be 2 to 3 feet tall, they develop numerous leaves. Varieties can also be identified by the smoothness (i.e., the Big Top Western strain, created at the University of Illinois11), "frilliness," or the crinkly texture (Common, Swiss and Sass varieties) of the leaves.

Similar to planting other herbs and vegetables, growing horseradish in the same place year after year can deplete the soil of beneficial organic matter and minerals. To remedy that, applying compost every fall is recommended. Beyond that, when you're ready to harvest, be careful to remove all the roots when harvesting, snip off the green leaves, wash the soil off and place them in a baggie in your refrigerator's crisper drawer.

Protecting Horseradish Naturally, and Why Growing Your Own Is Best

Like other plants, organically grown horseradish is not immune to disease and/or pests, but there are natural ways to both prevent most problems and solve them should they occur. Morning Chores12 and Off the Grid News13 tackle a few of the most common problems with growing crucifers, including horseradish, offering practical and natural ways to deal with each:

Imported cabbage moth larva — Watch for small white moths with tiny black dots on their wings, as they lay eggs that become this leaf-destroying pest. The best way to deal with these caterpillars is to pick them off by hand or place them in a bowl of soapy water.

Imported crucifer weevil — Metallic blue beetles with pointy faces produce larvae that bore into horseradish roots. You can use diatomaceous earth, which is a form of algae. It has sharp, microscopic edges that cut into insect bodies if ingested, destroying them from the inside out, but without being harmful to mammals.

White rust — This looks like white pustules on the plant, mostly due to being waterlogged or planted too closely together. Bacterial leaf spot starts as dark green spots that eventually turn brown. Sprayed liberally with a homemade fungicide made from horseradish itself may be an effective natural, DIY remedy:

"Process one cup of horseradish roots in a blender or food processor and mix with two cups of water. Let it sit for 24 hours and strain out the roots. Dilute this liquid with 2 quarts of water."14

The ease of growing horseradish makes it more fun than a chore, but there are other factors that may make the prospect even more attractive. At the grocery store or supermarket, if you take a look at the labels of several commercially produced horseradish preparations, you may notice more than the root and a little water; in fact, you might find surprising — not to mention unwanted — ingredients.

For instance, according to the manufacturers' labels, Rothschild's15 contains soybean oil and corn syrup. So does Woebers Sandwich Pal.16 Heinz Premium17 has soybean oil, sugar and high fructose corn syrup in it, as does Inglehoffer Cream Style Horseradish,18 which also adds the preservative sodium benzoate, which one study reported to be "clastogenic, mutagenic and cytotoxic to human lymphocytes" and "significantly increased DNA damage."19

Morrison's Hot Horseradish Sauce contains titanium dioxide for color, but one study shows it induces both DNA damage and genetic instability.20

So how easy is it to grow horseradish, someone may wonder? Boudier's answer is succinct as well as encouraging: "Make sure it's free of weeds, water it when it dries out, let it grow all summer and harvest it after the first frost."