Kohlrabi is harvested by pulling the entire plant out of the ground once it reaches a desired size. Kohlrabi’s flavor is best when the plants are small. If left in the garden too long, the plants become bitter and tough.
Another method is to watch the diameter of the stem as the plant grows. When it reaches approximately 1 to 3 inches at the base, cut the bulb from the root using a sharp knife. Remove the roots from the bottom of the bulbs, and trim the leaves and stems. The purple skin on the bulbs should be peeled before cooking them. The bulbs can be used in prepared dishes or raw and thinly sliced in salad. The leaves are similar to collard or turnip greens and can also be cooked in a variety of ways.
Growing kohlrabi is fairly easy. The plants do best in cooler weather. Early crops can be started indoors and transplanted in the garden when they are four to six weeks old. Most of the plant’s growth takes place in the spring and fall.
The plants should be grown in a sunny location with rich, organic and well-drained soil. Work at least 3 inches of organic material into the soil before planting. Leave 6 inches of space between plants and 12 inches between rows.