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Horseradish, Armoracia rusticana, is a thick root vegetable and part of the Brassicaceae family along with broccoli, cabbage, radishes, mustard, and wasabi (often called Japanese horseradish). It can be grown as an annual or perennial and is commonly used in American and European cuisine as a spice or part of soups, sauces, and spreads.

Horseradish is believed to have originated in Europe, where it was lauded for its medicinal properties through the centuries. In the United States, in a region of the Mississippi River floodplain called the ‘American Bottoms’ in southwestern Illinois, is where the vast majority of North America’s horseradish supply is grown.

Other states grow the root in lesser quantities, including California, New Jersey, Oregon, and Wisconsin. Canada also grows horseradish, and it is still cultivated in a number of European countries.

While the sturdy, tapered root is harvested for culinary use, the foliage has little commercial value today, though the leaves were used with the root back in the Middle Ages. Top quality roots are white, straight, and free of speckling or discoloration with a diameter close to 2 inches, weighing in at a couple pounds each. Horseradish root is most often ground or shredded, but can be dehydrated to lock in its pungent flavor.


Types & Varieties
Horseradish is a prized addition to many types of cuisine. The root is bought and sold fresh in small amounts (generally from a grower to restaurant or specialty seller) or sold in larger quantities for processing into condiments.

Varieties are based on the type of root and include Common (also called Maliner Kren), Czech (a newer cultivar), Bohemian (including Sass and Swiss), Big Top Western, Variegata, and Wild Root. When the root is crushed, shaved, shredded, or ground, it releases mustard oil, which is responsible for its ‘hot’ flavor and sharp, penetrating odor. Once roots are exposed to air, they will turn brown and lose intensity. Cooking will reduce pungency as well.

‘Prepared horseradish’ is the ground root mixed with vinegar to stabilize and preserve its flavor. The concoction is particularly popular in the United Kingdom, while various dressings and mayonnaise containing grated horseradish are sought after in the United States. Mixing with mustard is another centuries-old use, originating in Europe. More recently, due to declining availability of wasabi plants, horseradish (a close relative) has become a substitute in sushi dishes.

CULTIVATION

Horseradish is a robust plant, able to regenerate from small pieces of root. It is especially fond of potassium-rich soil, ample sunlight, and can be planted in spring or fall for harvest in late fall and winter (or left to overwinter till early spring).

Cultivation can be a lengthy process due to availability or inconsistency of planting material, necessary field preparation, and securing a relatively short list of approved pesticides. It can take more than one season to transition from initial planting to a marketable crop, so many growers keep a certain percentage of ‘sets’ or trimmed root sections to plant the next year.

If leftover root pieces aren’t managed properly once planted, horseradish can become an invasive weed in its own crop. Not only does this negate crop rotation, but plants will lose nutrients and have to fight against established roots to grow.



Pests & Diseases
There are a variety of insects that feed on horseradish root, some bringing other complications with them. Aphids, for instance, are known to spread turnip mosaic virus, hosted by nearby weeds and various plants, which will infiltrate crops. The virus is treated largely through varietal resistance and can be tolerated in small amounts.

Other insects worth noting are the imported crucifer weevil, caterpillars, horseradish flea beetle, two-dotted mites, cabbage worms or loopers, and the beet leafhopper.

Horseradish is generally robust enough to recover from foliage-eating insects before the late season harvest. For this reason, the few approved insecticides can manage crops with relatively light use.

There are not many pesticides for horseradish, though pre- and post-emergence herbicide applications are recommended. Fungicides are often used to treat foliar diseases such as white rust, bacterial leaf spot, ramularia leaf spot, and cercospora. Verticillium can cause root discoloration, affecting crops if untreated.

Storage & Packaging
Horseradish roots can be stored, wrapped in plastic, for months at cool temperatures (35 to 40°F) with high relative humidity. Packaging ranges from large shrink-wrapped pallets or burlap bags for commercial processing to small bags for specialty retailers and restaurants.

References: American Society of Horticultural Science, Herb Society of America, Horseradish Information Council, University of Arkansas, Virginia Cooperative Extension, USDA.

GRADES & GOOD ARRIVAL

Horseradish is graded as U.S. Fancy, U.S. No. 1, U.S. No. 2, or ‘unclassified’ by the USDA; U.S. Fancy requires roots be well-trimmed, well-shaped, and fairly smooth, free from decay and damage caused by dirt, sunburn, cuts, cracks, internal discoloration, mold, freezing, insects, or mechanical injury.

Roots must have a length of least 8 inches and 1.5 inch or greater diameter; if length exceeds 8 inches, the diameter can be slightly less but not under 1.25 inches.

For U.S. No. 1, roots must be firm, well-trimmed, fairly well shaped, not excessively rough, and free from decay and damage as mentioned above. Length must be at least 6 inches in length with a diameter of 1.25 inches or more; if longer than 6 inches, diameter may be slightly less but nor under 1 inch.

The U.S. No. 2 grade requires roots be firm, well-trimmed, and free from decay and serious damage. Roots must be at least 4 inches in length and not less than half an inch in diameter.


Generally speaking, the percentage of defects shown on a timely government inspection certificate should not exceed the percentage of allowable defects, provided: (1) transportation conditions were normal; (2) the USDA or CFIA inspection was timely; and (3) the entire lot was inspected.

U.S. Grade Standards Days Since Shipment % of Defects Allowed Optimum Transit Temp. (°F)
10-5-2 5
4
3
2
1
15-8-4
14-8-4
13-7-3
12-6-2
10-5-2
32°

There are no good arrival guidelines for this commodity specific to Canada; U.S. guidelines apply to shipments unless otherwise agreed by contract.

References: DRC, PACA, USDA.


This information is for your personal, noncommercial use only.