Do you have limited time and garden space, but want a variety of flavors and textures on your menu? Translated from German, Kohlrabi means is "cabbage turnip", and aptly so; a member of the cabbage family, kohlrabi tastes much like a cross between a sweet turnip and a mild radish.
Eat the leaves and stem raw, or prepare them any number of ways. Kohlrabi, in spite of or, perhaps because of its alien appearance (sometimes nicknamed "space cabbage"), is rapidly growing in popularity in markets and on menus. This hardy, fast-growing, versatile and visually stunning vegetable is a must for gardeners who want to make the most of their cool season crops.
Are you trying to encourage your kids to become more involved in gardening and healthy snacks? Get their hands dirty with their own space cabbage patch, and after harvest, help them make a batch of kohlrabi fritters or baked kohlrabi chips.
Add color and character to your garden, and flavor to your plate with Purple Vienna and White Vienna kohlrabi. The purple cultivar matures a few days later than its counterpart, but both varieties look stunning when planted together and are an excellent choice for those trying kohlrabi for the first time.
Soil Preparation & Requirements
Kohlrabi needs consistently moist soil and cool temperatures to prevent the stem from becoming bitter and woody. As this member of the cole crop family grows quickly, the plant requires rich soil amended with copious amounts of compost. Soil pH should be between 6.5 and 6.8.
Kohlrabi needs six hours of sun each day and thrives in temperatures between 40°F and 75°F.
Plant kohlrabi seed 1/4" to 1/2" deep.
Start seeds indoors six weeks prior to last frost in humus-rich, well-draining seedling mix. When seedlings are two to four weeks old, set flats outside to harden to cooler temperatures; at four to six weeks, transplant them in prepared rows 10-12 inches apart.
Kohlrabi mature in 50-65 days, depending upon variety and cultivation. For fall crops, plant kohlrabi with the goal of harvesting shortly after first frost date. Experiment with additional plantings a week or two later, and even a week before. Many growers claim that frost enhances the flavor of kohlrabi, and prefer to grow this unusual and delicious vegetable in fall. Use floating row covers or other protection to extend your season to the first hard freeze. Mature bulbs are very cold hardy, and in milder climates, do well left in the garden until you're ready to use them.
Kohlrabi in Containers
Due to their large, deep roots, kohlrabi is generally not a good candidate for container gardening, but given that we provide 500 seeds per packet, we encourage our patio gardeners to experiment with deep (18 inches or more) raised beds, six-gallon buckets, and other larger containers. As with all container gardens, pay special attention to watering needs, and protect containers and plants from overheating. Shade your container-cultivated kohlrabi in the hottest part of the day, or place them where they will get unobstructed, east-facing exposure.
Moisture & Fertilization
Never let soil dry out. Kohlrabi's tall growing habit doesn't provide shade to its own roots. Mulch will help retain consistent soil moisture and temperature as the plant matures, protecting flavor. Mulch right up to the base of the bulb, and add nitrogen-rich liquid fertilizer or side dress with mature compost every 2-3 weeks beginning when the plant is six inches tall.
Harvest kohlrabi when the bulb is firm and the stem is 1-3 inches in diameter. Cut the base of the stem (bottom of the bulb) with a knife. Store bulbs in the refrigerator for 2-3 weeks; greens should be used sooner, or blanched and frozen.
Incorporate baby kohlrabi year-round into your microgreens menu for flavor and color.
Kohlrabi is more resistant to diseases and insect pests than most of its cole crop cousins, but mulching and fertilization will help fend off clubroot and black rot disease, one of kohlrabi's common issues. Remove any plants showing signs of mildew, and check leaves and bulbs for insects and eggs.
Feel free to incorporate herbs, potatoes, alliums, beets and brassicas into your kohlrabi beds, but avoid interplanting with strawberries pole beans or tomatoes. Tomatoes, marigolds, and celery repel cabbage worms and cabbage moths.