Ruby Ball cabbage was bred to be a sweet, compact variety that matures a bit sooner than other cabbages and is slow to split when left in the ground. This is definitely a cool weather vegetable, but wait to put the starts out until the soil has warmed to at least 40 degrees and bury the stem up to the bottom leaves. Cabbages are prone to bugs, so consider using row covers for the entire growing season.
This beautiful red cabbage is loaded with healthful anthocyanins and other antioxidants not found in green varieties. Try making your own "fast" fermented kraut by shredding the leaves into 1/4" strips, then mixing and pounding with salt and the whey from yogurt to speed the process. Sandor Katz, the fermented food guru, has an excellent recipe online (just google it), or look for Sally Fallon's easy recipe in her book, "Nourishing Traditions." One of our gardening rebels has been making her own for years, so you can also ask Kathy when you stop by the nursery.