The connoisseur, however, continues to grow his own horseradish for the freshness. A few plants provide ample roots. Cultural Practices Horseradishes are started from crown divisions or root cuttings. Plant them whenever the soil can be worked in early spring. Place the roots 18 to 24 inches apart in shallow trenches and cover with a ridge or mound of soil to a depth of 4 to 5 inches.
Horseradishes grow best in deep, loose, fertile soil with abundant moisture.
Most gardeners grow horseradishes as perennials along one end of the garden and keep them weeded by shallow cultivation or heavy organic mulch. Apply water if the plants wilt during hot weather in the late summer and early fall. Leave some small, pencil-sized roots for next year's harvest or plant them in another row. Prepare your favorite sauce soon after digging. Surplus sauce can be frozen in small containers for year-round use.