This Pennsylvania Dutch heirloom traces to the historic village of Schifferstadt in the German Rhineland.  In the 1600s the entire village devoted itself to the cultivation of this now-rare heirloom variety, which was originally cooked much like turnips.  Brought to Pennsylvania in the 1700s, it thrives best in rich, light loamy soil.  The black skinned roots can reach a length of 12 to 16 inches and weigh several pounds.   Like daikon radishes, this old cultivar makes an excellent cover crop for loosening the soil.  Plant seeds 6 to 8 inches apart for best sized roots.  Since this a winter radish it should be planted in late August of early September.  It will overwinter in the ground in Zone 7 and warmer.  In colder parts of the country, lift in the late fall and store in tubs for replanting in the spring.