(Editor's Note: This article was originally published on February 3, 2008. Your comments are welcome, but please be aware that authors of previously published articles may not be able to respond to your questions.)
Pictures are courtesy of Gourmet Seed International.
Kohlrabi is a low growing stout member of the cabbage family and will grow almost anywhere. It has been selected for its swollen, nearly spherical, Sputnik-like shape. It does very well in well-drained fertile soil. I comes in both white and purple varieties.
When to Plant: Sow seeds in early spring. Make small plantings every 2 to 3 weeks for continuous spring and early summer harvest. For an especially early harvest, plants may be started indoors or in the greenhouse in flats to be transplanted into the garden as soon as the ground becomes workable. Like cabbage, kohlrabi plants can stand some frost. One or two late plantings can also be made in mid-summer at the same time as late cabbage. In very hot weather, these seedlings may benefit from some shade when they are small. I interplant them in and amongst taller plants I already have growing. We love them so much I usually buy extras of these seeds.
Spacing: The growers recommend sowing seeds in rows and cover them 1/4 to 1/2 inch deep. Thin the seedlings to 2 to 5 inches apart. We use the wide row method of gardening, so I had sow them in the area and thin with an iron toothed rake. You can also transplant the some of the surplus seedlings to fill in blanks in other parts of the row or into additional row space if more harvest is desired. The raked seedlings are great for tender, stir-fry greens.
Harvesting: Kohlrabi has the mildest and best flavor (resembling mild white turnips) when small. Large, older kohlrabi is tough and woody and it may have an off-flavor. Begin harvesting (pull or cut at ground level) when the first stems are about one inch in diameter. Continue harvest until the stems are 2 to 3 inches in diameter. When the stems get much bigger than 3 inches, they begin to develop woody fibers, especially in the lower part of the expanded stem. Even overgrown kohlrabi still may have some tender and tasty tissue at the top, where the youngest leaves continue to emerge as the plant grow.
Recommended eating: Kids love these both for their odd look and great taste. They are great raw straight out of the ground. My oldest son loves them this way and this year grew his own in his garden. I wonder if my DIL was looking for her salt shaker too? I use to find my salt shaker laying beside the row, LOL? They are great sauted with a little garlic, lemon juice, butter and a touch of sour cream. Peel the outer skin off and slice thin. There are some interesting recipes to be found by googling the web.
Diseases: They are subject to the same diseases as cabbage. I like to interplant them among the marigolds, just for the look and the marigolds keep most of the "pests" away.