The coloration of ornamental cabbage and kale is primarily influenced by temperatures below 55F (13C). A few production practices can help enhance the intensity of coloration, but discontinuing fertilization is not one of them.
Nighttime temperatures below 55F (13C) are the primary trigger for the development of head coloration in ornamental cabbage and kale. Growing the plants outdoors is the easiest method that allows one to take advantage of cool night temperatures. If the plants are grown under structures, allowing for as much ventilation as possible to cool the plants would help to quicken coloration.
As night temperatures become cooler, plant growth slows but does not stop. If one monitors the plant’s growth on a dry weight basis, it is easy to determine that ornamental cabbage and kale plants are
still growing even though the leaves in the center of the head are smaller. Those newly developing leaves require adequate fertility to mature.
Read the complete article at www.e-gro.org.