About Danish Ballhead Cabbage: Danish Ballhead cabbage descends from a variety of cabbage called Amager, dating back to the 15th century; it was cultivated on the island of Amager by Dutch colonists. W. Atlee Burpee & Company of Philadelphia offered Danish Ballhead to their customers for the first time in 1887.
Danish Ballhead Cabbage Germination: Start your seeds inside 8-12 weeks before the last spring frost, planting them in rich soil 1/2 inch deep and 2 inches apart. Because the first crop of cabbage should mature before the heat of summer, plant your seedlings about 4 weeks before the last expected frost; set them 12-18" apart in rows 3-4' apart, burying the stems about halfway up. For a fall crop, direct sow or transplant seedlings in midsummer. For companion planting benefits, plant cabbage with aromatic herbs or potatoes; avoid planting them with tomatoes or pole beans. Herbs such as thyme, peppermint, sage, and rosemary will repel the destructive white cabbage moth.
Growing Danish Ballhead Cabbage Seeds: If hard frosts come, cover the young plants; however, Danish Ballhead appreciates cool weather. Mulch around them to regulate soil temperature, and keep the soil moisture even to prevent the cabbages from splitting.
Harvesting Danish Ballhead Cabbage: Harvest the cabbages as soon as feel firm and reach a good size. Small cabbages tend to be more tender, while large cabbages from fall growth keep well over the winter.
Saving Danish Ballhead Cabbage Seeds: Late in the fall, mulch at least six different cabbage plants to ensure genetic diversity. If the climate is cold, digging up the entire plant and storing it over the winter will be necessary - keep it in moist sand at a temperature of about 40 degrees F. Replant 4-6 weeks before the last spring frost. If the heads are still firm, cut a deep X in the top to provide an easier exit for the stem. The stem will grow about 4-5' tall, with many four petaled yellow flowers. Allow the flowers to mature; when the seed pods form, pick them and allow them to dry. Remove them from the pods and store them in a dry, cool place for up to five years.
Detailed Danish Ballhead Cabbage Info: Brassica oleracea var. capitata. Biennial. 100 days. 6000 seeds per oz.12-18" height. 24-30" spacing. Produces 5-7 lb. round cabbages.