Ornamental cabbage and kale look especially good in a large planting, where their color really stands out. Since they are low growers, you’ll often see them as edging plants, where their purplish hues blend in well with other fall colors. If you only want 1 or 2 plants, they look less out of place in containers, than they do scattered throughout a garden. In fact, they make nice, long lasting replacement plants for spent summer containers.
When buying plants, opt for larger plants, once cabbages get root bound, the top portion becomes stunted and will never fill out the way you'd like. Look for plants with short stems and relatively uniform length leaves, no holes and at least a hint of color
Cabbages and kales prefer to be grown in cool weather. Although you can plant them out at anytime, the colorful pigmentation doesn't develop until after frost or prolonged cold weather. If you plant them too early in the fall or late summer, the plants will get leggy and remain green. Both cabbages and kale prefer a slightly acidic pH of about 5.8 - 6.5. They like to dry out slightly between watering, but stress if left dry for prolonged periods.