Kohlrabi is also known as German Turnip. You’ll often see kohlrabi at the local farmers’ market. Still, you may not know what to do with such an impressive-looking vegetable.
The plant has a mild flavor and is versatile in numerous types of cooking. Not only will you learn to grow kohlrabi in your garden, but we’ll also show you how to use this nutritious plant in the kitchen to make meals your family will love.
What is Kohlrabi?
Kohlrabi is a bizarre-looking vegetable. Its root base is globe-shaped and looks like an out-of-this-world turnip with cabbage-like greens. Don’t let the strange appearance turn you off from this unique vegetable. It grows well in the U.S. and provides a delicious alternative to bland, overused ingredients in salads, soups, stews, and other tasty culinary treats.
Kohlrabi is a cool weather plant that grows best when planted in early spring or late summer as an annual. It can tolerate frost once it’s established, but young plants will need to be protected from cold snaps. Kohlrabi doesn’t grow well in hot temperatures, so gardeners in the U.S. who regularly see summertime temps over 85 degrees should anticipate two growing seasons.
What Does It Taste Like?
The round root base has a flavor similar to a cross between cabbage and broccoli. The root is peeled and can be eaten raw or cooked.
The greens are edible and make for an excellent addition to garden salads when young or can stand in for spinach or mustard greens when fully mature. Kohlrabi goes very well with Indian spices and makes a delightful fritter when shredded and fried.
How to Grow Kohlrabi
The kohlrabi plant family can be tricky to grow in many parts of the U.S.
It’s essential to start plants at the right time of the year and harvest before the weather gets too hot to get a good production. U.S. gardeners can succeed in growing this unique vegetable by following some simple tips to get the garden ready and boost healthy, vigorous Kohlrabi plants from seeds.
– Starting With the Seeds
Kohlrabi is a cool, weather-loving vegetable. In the U.S., start seeds several weeks before the last frost. You’ll likely have the most success starting kohlrabi seeds indoors.
A great trick is to soak kohlrabi seeds for several hours up to overnight to help moisture penetrate the seed’s outer layer. Soaked seeds can be planted in a seedling tray, or they can be placed in a damp coffee filter or paper towel until the seeds sprout.
– How to Plant the Seedlings
Kohlrabi seeds can go into your garden well before the last frost, up to three weeks in most regions. The seeds will germinate in cool temperatures when soil temperatures are around 50 degrees.
Ideally, plant kohlrabi in spring because it will need between 45 and 60 days to mature. It won’t grow well once temperatures exceed average daily temps above 75 degrees, so you’ll need to plan to grow young kohlrabi plants.
Seedlings should be planted in rows with seeds set about one inch deep and four to six inches apart. A staggered double row when planting kohlrabi is a great way to get more production from small spaces. Thinned seedlings transplant well, so don’t be bashful about moving healthy shoots to a different part of the garden when you reduce the number of plants in your rows.
Succession planting is also a great idea if you are planning on harvesting a fair amount of kohlrabi. Suppose you plant seeds every three to four days over the course of two weeks. In that case, your kohlrabi will mature in stages so you can harvest fresh kohlrabi without having to find ways to use or store large quantities at once.
– Ideal Soil Conditions
Kohlrabi will grow best in garden soil rich in nutrients, well-turned, and drains very well. Gardeners should mix a few inches of aged compost into the garden soil before planting to give young plants a boost in nutrients.
Once your plants are well established and about two months into their growth, you can side-dress your garden with an organic fertilizer to boost growth.
– Optimal Light and Temperature Conditions for Kohlrabi
Kohlrabi requires full sun locations for vigorous growth but will suffer significantly if temperatures are too high. The ideal temperature range for kohlrabi plants is 40 to 75 degrees.
Temperatures above or below this range will prevent the plant from growing its desirable stem globe. Kohlrabi should be planted in the very early spring or late winter in most parts of the U.S. to grow vigorous plants before high summer temperatures begin.
– Watering Kohlrabi Plants
Proper watering is essential for excellent growth from your kohlrabi plants. The soil must be kept consistently moist but not allowed to get soggy or waterlogged. Kohlrabi plants that are allowed to dry out between watering will develop woody, appealing stem balls. Drip irrigation is highly recommended to allow proper watering. Kohlrabi roots spread along the surface, so regular, shallow watering is ideal.
– Weeding and Upkeep
Young kohlrabi plants can quickly become choked out by overgrown weeds. Gardeners must use caution when removing weeds around young kohlrabi plants.
The roots are shallow and can quickly become disturbed and damaged by pulling weeds. A great trick to use when weeding around young kohlrabi plants is to use a pair of small, sharp scissors to cut the weeds off at ground level.
When to Harvest
Kohlrabi is usually ready to harvest between 45 days and 60 days after sprouting. Gardeners should keep an eye on the stem ball that grows and harvest kohlrabi plants before the ball exceeds three inches in diameter. Larger stem balls become tough and woody and don’t taste very good.
You can harvest kohlrabi greens throughout the growing season, be sure to leave the center leaves growing to prevent killing the plant. It should be added that the kohlrabi fall harvest is the best time of all.
– How to Harvest
Harvesting is simple. When your kohlrabi bulbs are ready, you can pull the entire plant. Alternatively, use a sharp knife or shears and clip the stem ball just above the ground. The roots will help to fertilize your garden soil but are unlikely to resprout. You can harvest greens throughout the growing season by cutting them from the plant with a sharp knife.
Don’t tear the leaves off because you can expose the plant to diseases and the wounds create an opening for pests.
How to Store Fresh Kohlrabi
Storing kohlrabi depends on the season. You will reserve the stem balls differently for a spring harvest than for a fall harvest.
During the spring, cut and harvest the kohlrabi as soon as the balls are about two and one-half inches in diameter. Wash them thoroughly and keep them in the refrigerator. They will stay fresh for two to three weeks in the fridge.
In the fall, you can leave the kohlrabi in the garden. Once the bulb has gotten to the appropriate size, just cut the greens off, and the plant will stop growing. Cool temperatures will keep it fresh for weeks, and even a frost or light snow won’t damage the bulb. This way, you can have fresh kohlrabi on demand all winter.
– Freezing Kohlrabi for Long-Term Storage
If you want a long-term storage solution, clean your freshly harvested kohlrabi and peel the outer layer with a paring knife. Cut the kohlrabi into cubes and place them in a resealable freezer bag. Be sure to press out as much air as possible, then put the cubes in the freezer. They will stay fresh for about three months in the freezer. Frozen kohlrabi should be defrosted in the refrigerator before use in your favorite recipe.
How to Use Kohlrabi
Now that you have grown a stunning and beautiful crop of delicious kohlrabi plants, you will want to know how to cook them. There are many popular ways to use kohlrabi.
In most cases, the outer layer of the kohlrabi bulb will need to be peeled. A paring knife or a vegetable peeler works very well to remove the tough skin. Cube kohlrabi into one to two-inch pieces and saute in a pan with butter, garlic, and onions. It brings out the mild, cabbage-like flavor and enhances other seasonings in your pan.
A great way to serve kohlrabi for people who don’t like to eat their vegetables is to use a grater and shred the kohlrabi. Squeeze the moisture from the shredded bits and mix in a few tablespoons of cornstarch, then press into patties. Fry in a small amount of oil until golden brown. These kohlrabi fritters are a delicious way to use your harvest and are a favorite of picky eaters.
Preventing Pests and Diseases
Gardeners should learn to identify signs of pests and diseases and act quickly to prevent severe damage to their crops.
Many pests and diseases can transfer from one type of plant to another, so any problems must be addressed right away. Kohlrabi plants may be less susceptible to specific problems simply because they do best in cool temperatures when many of the worst pests are dormant. It is particularly true for fall harvests.
– Signs of Pests
In the U.S., several pests will happily ruin your kohlrabi plants. Among the most common, flea beetles and cabbage loopers are a particular problem. Flea beetles are small black insects that eat irregular holes in leaves. Left to their own devices, flea beetles will damage crops, slow or prevent growth, and kill the plants. They are also responsible for spreading diseases.
Cabbage loopers are the larvae of white butterflies. These pernicious pests chew through leaves and stems. One of the worst things about cabbage loopers is they will eat a little of one leaf, then move on to another, eventually causing a tremendous amount of damage.
Cabbage loopers can be controlled by using row cover to prevent butterflies from landing on your plants. Flea beetles are easily managed with neem oil spray or diatomaceous earth. It’s also a good idea to plant varieties of plants that attract beneficial pollinators predatory to pests like lady beetles and wasps.
– Signs of Disease
The most frequent diseases that impact kohlrabi plants are root rot and mildew. Both situations can be prevented by using treated seeds, clean soil, and appropriate watering techniques. Most diseases are the result of pathogens found in the soil or growing on low-quality seeds. These issues are prevalent when gardeners overwater their garden or spray water on leaves during cool weather.
Diseases are much less common in fall, just like pests. Buying good-quality seeds is a significant preventative step. You’ll notice yellowing leaves, wilting, lesions, and soft, yellow stems when diseases impact the growth of your kohlrabi plants. Infected plants need to be removed and destroyed. You should rotate your crops so that species related to cabbage are not planted in the same place more than two years in a row to prevent disease spread.
What to Plant with Kohlrabi
There are lots of great companion plants that prefer cool temperatures and similar watering. Beets, celery, and cucumbers are popular companions.
You should avoid planting brassica species like cabbage, bok choy, or cauliflower near kohlrabi to avoid spreading common diseases and pests.
- Kohlrabi is a unique vegetable that prefers cool weather.
- Its short growing season makes for an ideal early spring, late summer planting.
- Kohlrabi can be grown from seed starting indoors well before the last frost and can be sown in the garden up to three weeks before the last frost.
- Kohlrabi plants prefer rich soil that drains well, full sun, and consistent, shallow watering.
- You can harvest kohlrabi leaves all season, and the bulbs are ready once they are less than three inches in diameter.
- Kohlrabi can keep it in the fridge for three weeks or be frozen for several months. Fall crops will stay fresh when left in the garden.
- Pests and diseases are uncommon due to the cold weather climate kohlrabi prefers. Still, gardeners should be on the lookout for flea beetles, cabbage loopers, mildew, and root rot.
- Grow kohlrabi with other cold-weather performers, but avoid planting with other brassica species to prevent crossing pests and diseases.
Kohlrabi is a bizarre-looking vegetable that you might think needs specialized gardening tips to grow. It’s relatively easy to develop a cabbage cousin that produces tasty stem bulbs you can use in various recipes, fresh or cooked.
The next time you are at the farmers market and see this alien-looking vegetable, you’ll know that it’s a star for cold weather planting.