Want to heat up your life when the temperatures drop this winter? For home gardeners, horseradish could do the trick.
My good friend John Gerber, then-an extension vegetable specialist at the University of Illinois, used to tell me that Illinois led the country in the production of horseradish. He said more horseradish is grown in Illinois than any other place in North America.
But you don’t have to live in Illinois to enjoy it. Recently, I was giving a tour of the Penn State high tunnels for Ag Progress Days and was pointing out the horseradish that we have growing in a tunnel. It’s something that you can grow in your own garden, too.
Horseradish, or Armoracia rusticana, is a hardy perennial that is a member of the Brassicaceae family and is grown for its white, thickened and pungent roots. The large primary roots are fleshy with a smooth or corky surface. The intense pungency of horseradish roots is caused by isothiocyanate compounds released from the glucosinolates sinigrin and 2-phenylethylglucosinolate by the naturally occurring enzyme myrosinase found in the plant. New Bohemia and Maliner Kren are two common varieties.
It is likely that horseradish originated in the temperate regions of Eastern Europe and probably had its name derived from the old German word “meerrettich” meaning “sea radish” as the plant grew wild in European coastal areas, and this term was most likely mistaken by English speakers as “mareradish,” later becoming horseradish.
Horseradish is indeed a condiment capable of clearing sinus cavities and savored in sauces for seafood, pork and beef dishes. I guess it could knock over a horse.
Horseradish is a true perennial in the garden along with rhubarb and asparagus, but commercially it is produced as an annual. Home gardeners can get those large roots that are easier to peel and process by adapting the techniques that commercial growers use.
Start by planting horseradish in the fall or very early spring. Use root pieces (sets) that are finger width in diameter and about 12 to 18 inches long. Till the garden and lay the sets horizontally, with the head (large end) slightly elevated. Cover the sets with six to eight inches of soil, forming a ridge 1 to 2 feet wide.
Believe me when I say that a few plants are usually plenty for the home gardener. Horseradish will require limited amounts of either compost or fertilizer and a 10-10-10 or 6-24-24 can be used. The main thing is that it is important to limit the amount of nitrogen so that growing energy is directed into the root. Too much nitrogen may cause excessive top growth and branching of the roots.
During the growing season, crowns with multiple shoots form above the ground, while the original set grow in diameter with many side roots forming underground. The goal is to grow the original set as large as possible. Either suckering or lifting can achieve this.
Suckering is done by removing all but one or two leaf shoots at the head end as they develop. Lifting is simply digging through the ridge and gently lifting the crown end with a hoe to break roots forming at the crown. This forces side roots to form at the tail end. This should be done a couple of times during early and mid season. Both methods will result in greater swelling of the initial root, producing a large 1- to 2-pound main root at harvest. Once the top leaves are frozen in late fall, harvesting can begin.
Go ahead and dig the large central root and as much of the secondary root system as possible. Be sure to save side roots for planting the next year’s crop. Dug roots can be stored in the refrigerator for many months. Wrap them in plastic to conserve root moisture. Horseradish can be harvested as needed throughout the winter and even into the spring.
This method breaks side roots that grow into new plants, more plants than most gardeners would want. To keep horseradish from taking over the garden, I would enclose it in some type of frame to keep it from spreading, similar to growing Jerusalem artichoke.
Home gardeners can process horseradish by peeling and dicing the root pieces, and then grinding in a blender.
A basic recipe is to fill a blender half full with diced horseradish, add a small amount of water and ice, and grind to desired consistency. To preserve and enhance the flavor, add two or three tablespoons of white vinegar (not cider vinegar) and a half-teaspoon of salt or one tablespoon of sugar.
Vinegar stops the heat-building enzyme activity caused by crushing. So for a milder sauce, add the vinegar immediately. For a hotter sauce, wait a few minutes after grinding before adding the vinegar. Place in clean jars and don’t fill the jars too full. Cover tightly, and store in the refrigerator or freezer.
Bill Lamont is a professor and extension vegetable specialist in the department of plant science at Penn State. He can be reached at firstname.lastname@example.org.