If you want to plant horseradish, now is the time! Spring is the season—but only in places where winters freeze hard. Here’s how to plant, grow, and harvest horseradish in your garden.
An exceptionally hardy perennial, horseradish belongs to the venerable plant family Cruciferae (“cross-bearing,” for the tiny, cross-shape flowers characteristic of all members of this family), which includes cabbage, broccoli, cauliflower, brussels sprouts, among other commonly-grown vegetables.
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 from many local garden supply stores.
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.
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 bring the two compounds together. The finer the grating or grinding, the more pungent and richly flavored the root becomes.