Kohlrabi is a hardy biennial grown as an annual. Sow kohlrabi seed in the garden 3 to 4 weeks before the last average frost date in spring. Kohlrabi grows best in cool temperatures between 40°F and 75°F. Kohlrabi requires 45 to 60 days to reach maturity. In warm winter regions, sow kohlrabi in late summer for winter harvest. Kohlrabi can withstand an early autumn frost.
Description. Kohlrabi is a hardy biennial grown as an annual. Kohlrabi has a swollen globe-shaped stem that makes it look like a turnip growing on a cabbage root. Stems can be white, purple, or green and is topped with a rosette of long-stemmed blue-green leaves. Kohlrabi is milder and sweeter than either cabbage or turnip.
Yield. Plant 4 to 5 rutabagas per household member.
Site. Plant kohlrabi in full sun. Grow kohlrabi well-worked, well-drained soil rich in organic matter. Kohlrabi prefers a soil within the 5.5 go 6.8 range. Work aged compost into planting beds before sowing. Side dress kohlrabi with aged compost at midseason.
Planting time. Kohlrabi is a cool-weather crop. Sow kohlrabi seed in the garden 3 to 4 weeks before the last average frost date in spring. Kohlrabi requires 45 to 60 days to reach maturity and should be grown so that it comes to harvest before temperatures average greater than 75°F. In warm winter regions, sow kohlrabi in late summer for winter harvest. Kohlrabi can withstand an early autumn frost. In cold winter regions, sow kohlrabi in summer for early autumn harvest.
Planting and spacing. Sow kohlrabi seed ½ inch deep and 1 inch apart; thin successful seedlings from 5 to 8 inches apart. Space rows 18 to 24 inches apart. Thinned seedlings can be transplanted to another part of the garden.
Water and feeding. Keep soil evenly moist for quick growth. Kohlrabi that goes without water will become woody. Prepare planting beds with aged compost. Side dress kohlrabi with aged compost at midseason.
Companion plants. Beets, celery, herbs, onions, potatoes. Do not plant with pole beans, strawberries or tomatoes.
Care. Cultivate carefully to avoid harming the shallow roots. Mulch kohlrabi with aged compost when plants are 4 to 5 inches tall.
Container. Kohlrabi is large rooted and not well suited for container growing.
Pests. Kohlrabi can be attacked by cutworms, cabbage loopers, and imported cabbage worms. Place collars around stems to protect seedlings from cutworm damage. Remove egg clusters from underneath leaves and wash plants with dilute soap solution. Cabbage worms can be controlled by spraying with bacillus thuringiensis.
Diseases. Kohlrabi is susceptible to cabbage yellows, clubroot, and downy mildew. Plant disease resistant varieties. Remove and destroy infected plants.
Harvest. Kohlrabi is ready for harvest when stems reach 2 to 3 inches in diameter.
Varieties. Early Purple Vienna (60 days); Early White Vienna (55 days); Grand Duke (50 days); Purple Danube (52 days);
Storing and preserving. Kohlrabi will store well in the refrigerator for 1 week or for one to two months in a cold, moist place. Kohlrabi can be frozen.
Common name. Kohlrabi, turnip-rooted cabbage, stem turnip, turnip cabbage
Botanical name. Brassica oleracea, Gongylodes group
Origin. Hybrid
Grow 80 vegetables: KITCHEN GARDEN GROWERS’ GUIDE
I am having a problem with radicchio. My gardening friend and I planted it years ago in spring; it never came to a head. My friend read somewhere that it was a two year plant. We planted seedlings late last spring and now I have a healthy plant, cupping leaves but no sign of a head. (I don’t know the variety we planted.) So, what am I doing wrong?
Persuading radicchio to form a head can be difficult, but not impossible. Only 10 to 50 percent of heading varieties actually form a head without special attention; so you can see success can be difficult Here are a few suggestions to get the results you want:
1. Choose a variety that more easily heads, here are several in order or best success: Indigo, Fiero, Chiogga Red, Prima Rosa, Carmen.
2. Plant for fall harvest: sow seeds in the garden 85 days before the first frost in fall; radicchio requires a long, cool season. Spring planted crops have less success.
3. Place a plastic mulch or plastic sheeting around the radicchio plants–white, black, or clear. Growing radicchio on plastic, not the soil, will increase the heading percentage significantly.
Finally, radicchio leaves can be eaten even if a head does not form; so once leaves are 4 to 5 inches long harvest them from the outside in cut-and-come-again fashion and enjoy the flavor of young, tender leaves.
I planted kolrabi between peppers and tomatoes. Two questions: Why are they so small, just ping-pong ball size? Why arent you supposed to plant kohlrabi by tomatoes?
Small Kohlrabi: Kohlrabi likes cool weather. It is fast growing and matures quickly, so it is a good choice spring and fall planting. Direct-seed kohlrabi about the time of the last spring frost date and for a fall crop about 8 to 10 weeks before the first fall frost date. If you live in a region where summer weather does not get too warm, you can make successive sowings of kohlrabit every 2 weeks. Kohlrabi is best harvested young and small, when the bulbs are about 2 inches in diameter–this size kohlrabi will be sweet, crisp, and tender. If bulbs get too much bigger they will turn woody and fibrous. Kohlrabi is a member of the cabbage family–to allow for the simple management of pests and diseases–and because the growing requirements are different, it’s best, but not essential, that you plant kohlrabi away from tomato family vegetables.