I am growing dwarf ornamental kale to use in flower arrangements. I would like to use them in June. They are growing nicely but I cannot simulate the cold temps and sunlight needed for development of the purple color. Would it be possible to place them in a refrigerator at night and put them in warm partial sunlight during the day for color?? They are about half their final size at this point. Thank you!
Ornamental Kale Color
Certified GKH Gardening Expert
It might, actually, help a little, but it will be at the cost of the plant's health. Going from cold to warm everyday will stress the plants very badly. Kale is more suited for cooler climates, so if you are not in a cooler area, then it will be difficult to force them into color.
Now, using an LED panel with reds and blues can force some of the purple color out. Using UV bulbs SPARINGLY can help force coloration as well. This can help force anthocyanin production, which will be responsible for the purple color.