kohlrabi (Brassica oleracea) Profile

Written by Iris

Aug 18 2021

kohlrabi (Brassica oleracea) Profile
Kohlrabi (Brassica oleracea) is similar to tennis balls sprouting kale leaves. kohlrabi (Brassica oleracea) looks strange but tastes good. The leaves and petioles of kohlrabi (Brassica oleracea) relative are edible, but most gardeners grow it for the enlarged spherical parts that form above the soil surface. kohlrabi (Brassica oleracea) is probably native to Western Europe.

kohlrabi (Brassica oleracea) Picture


kohlrabi (Brassica oleracea) Info

Botanical Name Brassica oleracea
Common Names Kohlrabi; German turnip
Plant Type Herbaceous biennial
Mature Size 18 inches tall, 18 to 24 inches wide
Sun Exposure Full sun
Soil Type Rich, moist loam
Soil pH Slightly acidic (5.5 to 6.9)
Bloom Time Summer

kohlrabi (Brassica oleracea) Distribution Area

Kohlrabi, also known as German turnip or cabbage turnip, is very popular in Northern and Eastern European countries like Germany and Hungary as well as northern Vietnam and eastern India.

How to Grow and Care for kohlrabi (Brassica oleracea)

How to Grow kohlrabi (Brassica oleracea)

  • With Seeds
Kohlrabi can be started indoors in seed trays or have their seeds sown directly into the ground. Combining the practice of both methods can ensure the successful harvest of these vitamin-rich garden gems.
Plant seeds indoors approximately 4 to 6 weeks before the final frost.
Direct sow seeds directly in the garden bed in mid to late summer to grow a fall or early winter crop.
Seeds should be planted at a depth of ¼ inch to ½ inch.
Transplant seedlings when they are 3-4 weeks old and after the danger of frost has passed.
Plant root balls of transplants so that they are level with the ground so that the bulbous portion will grow above the soil and not rot out.

How to Care for kohlrabi (Brassica oleracea)

  • Light
Kohlrabi needs a full day of sun to grow plump and develop its characteristic flavor. Because this is a fast, early-season vegetable, you may be able to plant it near deciduous trees that haven't leafed out yet.
  • Soil
Kohlrabi needs fertile and well-drained soil to grow and produce healthy stems, leaves, and its bulbous base. Mulch the soil with plenty of organic matter for added nutrition and water absorption. Loose, well-worked soil is best for your kohlrabies to truly shine. The ideal soil pH level for growing kohlrabi ranges from 6.0 to 6.8.
  • Water
When the kohlrabi has established itself, it will require about 1 to 2 inches (2.5 to 5 cm) of water a week. You should water multiple times a week, being careful to avoid over-saturating the soil, in order to limit the risk of causing any rot, molds or fungus from infecting your plant.
  • Temperature and Humidity
Like many cruciferous vegetables such as broccoli and Brussels sprouts, kohlrabi grows best in cool weather. When summer temperatures arrive, kohlrabi is done growing. Plants you didn't get around to harvesting will be prompted by warm weather to bolt, or produce flowers.
  • Fertilizer
Fertilizing kohlrabi is a little tricky as they're heavy feeders. Start with rich soil, to begin with, and side-dress every few weeks with well-rotted cow manure. Alternately, begin with the rich soil but opt for regular fertilization using a nitrogen-rich fertilizer. A 10-5-5 should suffice, but follow manufacturer's instructions for the frequency of application.

Uses of kohlrabi (Brassica oleracea)

  • Edible Uses
In the kitchen, you can serve kohlrabi raw as part of a raw vegetable platter, sliced into a salad or grated into a slaw. You can also slice and use it in stir-fries or sautés. Delicious kohlrabi is crunchy, juicy, and has a mild, sweet, “cabbage” flavor. Once harvested, the leaves are also tasty. You can use the leaves as cooking greens.
  • Medicinal Uses
Kohlrabi is taken by mouth as an antioxidant and for cancer, heart disease, constipation, diabetes, gout, hemorrhoids, hot flashes, high cholesterol, liver disease, menstrual symptoms, a pain disorder called sciatica, scurvy, weight loss, and wound healing. Kohlrabi is applied to the skin for hair loss.

Varieties of kohlrabi (Brassica oleracea)

Kohlrabi belongs, like kale, cauliflower, or white cabbage, to the cabbage family. Basically, a distinction is made between early and late varieties on the basis of their sowing and harvesting times. However, there are now also many varieties of kohlrabi that can be grown throughout the season. Plants with light green to almost white tubers and green leaves are the most common in this country. A classic is the Superschmelz variety; its yield can weigh several kilos, and yet it remains very tender! If you prefer a bit more color, there is also kohlrabi with blue-violet-veined leaves and shells, such as Azur Star and Blaro. Their tubers grow and ripen more slowly, but taste even more tender than the white ones.

kohlrabi (Brassica oleracea) Common Pests/Diseases

When growing vegetables, it is always exciting to care for the plant throughout its growing phase and then harvest it for delicious recipes later on, but one thing to watch out for is pests and diseases. Different plants are susceptible to different types of pests and diseases, and Kohlrabi can fall victim to several different pests and diseases, many of which are similar to the problems affecting greens.


A few of the common pests affecting kohlrabi include the beet armyworm, the cabbage aphid, the cabbage looper and more.
THe beet armyworm will cause leaves to appear skeletonized due to heavy feeding. Use organic methods to control this insect such as Bacillus thuringiensis.
Cabbage aphids can stunt plant growth and even cause death. THe insects are gray-green and will be visible on the leaves. These aphids only feed on cruciferous plants but can survive on related weeds. If the infestation isn’t bad, prune out the affected leaves. However, if the infestation is heavy, spray the sturdier plants with a strong jet of water to knock the aphids off the leaves.
Cabbage loopers will cause extensive damage in the leaves. The caterpillars are green and have white lines on each side of their body. They will overwinter in crop debris. Handpick the larvae off the plants or apply Bacillus thuringiensis to kill the younger larvae.


Some of the common diseases affecting kohlrabi include Alternaria leaf spot, black rot, damping-off, clubroot, downy mildew and more.
Alternaria leaf spot will cause small spots on the leaves that are darker and will later turn brown or gray. Lesions may appear round or angular. The lesions may then form rings and become brittle and crack. This disease is most likely to become a problem during cool, wet periods. The best ways to prevent this from happening is by planting pathogen-free seeds, practice crop rotation and apply the correct fungicides to control the Alternaria leaf spot when it occurs.
Black rot will cause seedlings to develop yellow or brown leaves that wilt and collapse. It is most prevalent in warm, wet conditions. To control this disease, practice good sanitation, plant disease-free seed and rotate crops.
Damping-off will kill seedlings after they germinate. Symptoms include black rot girdling on the stem, and the seedlings may remain upright but the stem will appear constricted or twisted, which is why damping-off also is known as wirestem. It favors cool temperatures. To prevent this, plant pathogen-free seeds and apply fungicides when necessary.
Clubroot will cause plants to be slow growing or stunted, and the leaves will turn yellow and wilt during the day. To avoid this disease from occurring, plant certified seeds and apply lime to the soil.
Downy mildew will cause irregular yellow patches which turn brown. These patches are located on the leaves. A gray growth will appear on the bottom of the leaves. The disease is more likely to occur when the environment is cool and wet. To prevent this, remove crop debris and practice good crop rotation.

kohlrabi (Brassica oleracea) Harvesting

kohlrabi (Brassica oleracea) is usually harvested at tennis ball size. Most gardeners will tell you that if left to get any larger it will get tough and woody. As long as you keep the plant well watered and fed larger kohlrabi (Brassica oleracea) will be just as tender as small ones. Clearly don't take this to the extreme, big old plants will taste like your kitchen table.
Pull the stems and root from the ground or cut below the stem with a sharp knife. kohlrabi (Brassica oleracea) doesn't store well so harvest as you need it, if you want to store kohlrabi for several weeks, remove the leaf stems and place, unwashed, in sealed plastic bags in the refrigerator.
The leaves are also edible. They can be added to salads, or boiled like spinach.

kohlrabi (Brassica oleracea) Companion Plants

Good companion plants for kohlrabi are brussels sprouts, kale, cabbage, onions, garlic, cauliflowers, beets, cucumbers, celery, potatoes, shallots, mustard, thyme, broccoli and lettuce. You should not plant kohlrabis with sunflowers, beans, tomatoes, melons, pumpkins and strawberries.