Experienced kale growers, knowing the crop's preference for cool weather, sow seeds of their favorite varieties in flats in midsummer for late-midsummer transplanting to the garden. It's often too hot at that time of year to start seeds in a greenhouse, so try the trick of starting them in the partial shade of large trees. Be sure to keep the flats well-watered.
Here are tips for how to grow your own kale:
For transplanting, choose a sunny, fertile spot with lots of compost in the soil. If possible, plant your kale on a high spot that is well-drained but still out of the wind. This will help to extend the bounty of the crop into the winter time. Space the seedlings 14 inches apart in all directions, or 12 inches apart in rows 2 feet apart.
Aphids can get established early and persist on your kale if you don't have enough insect predators in the vicinity of your garden. Ned Herbert, farm manager of the Abundant Life Seed Foundation, says he tries to always have flowering members of the Umbel family, which includes dill, coriander and bronze fennel, in the garden to attract parasitic wasps that prey on aphids.
You also can remove aphids with a strong spray from your hose. As for cabbageworms, the easiest organic answer is to spray Bacillus thuringiensis (Bt). Be sure to use the version of Bt that is labeled for caterpillars. Plants mature for harvest in 50 to 80 days. To freeze your bounty, treat it just like spinach: Blanch in boiling water, plunge into iced water to stop the cooking, package in freezer bags and label.
Kale Seed Sources
Abundant Life Seed Foundation
Port Townsend, Wash.
William Dam Seeds
Dundas, Ontario (Canada only)
Johnny’s Selected Seeds
Seeds of Change
Santa Fe, N.M.
Territorial Seed Co.
Cottage Grove, Ore.
Baked Kale Chips Recipe
Baked Kale Crackers Recipe
Black Kale Salad Recipe
Caldo Verde: Portuguese-Style Kale and Potato Soup Recipe
Salt and Vinegar Kale Chips Recipe
John Navazio, Ph.D., is director of seed grower development at the Abundant Life Seed Foundation in Port Townsend, Wash., and owner of the organic seed company Seed Movement in Bellingham, Wash.