The darkest of the blue-green kales, Darkibor kale seeds produce plants that have finely curled leaves with intense flavour. This is an early-maturing kale for late summer and fall harvests. Plants are upright, easy to grow, and ideal for multiple harvests. Its dark leaves make very nice garnishes. Plant Darkibor kale seeds in your organic vegetable garden for a continual harvest of nutritious kale. Chopped or minced kale leaves release the highest amounts of sulforaphane, the cancer-fighting compound found in all Brassicas. Boiling kale reduces the effect of sulforaphane, but steaming and microwaving appears to conserve it in the leaves.