Horseradish

Gardening by the Yard : Episode GBY-404 -- More Projects »
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Horseradish is a plant worth growing, provided you keep its growth in check. Horseradish roots can be planted in spring or fall, roughly 2 to 4 inches deep and 1 to 2 feet apart, preferably in full sun. They also need plenty of moisture, especially during the summer. In most areas of the country, the roots can be harvested in October or November.

To prevent the plant from spreading, harvest all but a little bit of the root. You can also plant horseradish in a bottomless pot, much like you would mint or a spreading bamboo.