Fresh horseradish root can be purchased at most American supermarkets throughout the year. The prime season for the spicy white root is springtime. Choose mold-free, unwilted root sections that have no green spots, soft spots or sprouts.
Fresh horseradish root can be loosely wrapped and kept for several weeks in the crisper drawer of a refrigerator. Once cut or grated, horseradish should be used immediately. For extended storage, cut horseradish root into one-serving slices, wrap tightly in plastic and store in the freezer. Alternately, horseradish root slices can be covered with vinegar and stored in a sealed jar in the refrigerator. Horseradish roots for growing in the garden can be purchased at AsparagusGardener.com.