If you ever wanted to grow a vegetable in your garden that would have your friends and family stopping in their tracks, pointing, and exclaiming, “What is that?” then you’ve got to consider growing kohlrabi.
Kohlrabi is a unique plant that many people don’t include in their cooking – let alone in their garden plans. However, it’s one that I think everybody should. It is an incredibly low-maintenance plant that requires minimal care and upkeep, plus it’s absolutely delicious to eat.
This plant is somewhat like a combination of kale and turnips. It’s grown for its stem, which grows like a bulb – but above the ground instead of underneath it.
If you’re new to growing kohlrabi and want to start, here are some tips on growing kohlrabi step by step.
Why You Should Grow Kohlrabi
Kohlrabi is a tough plant that looks a lot like a turnip growing on a cabbage root. It produces stems that can be green, purple, or white, and are topped with a gorgeous display of long bluish-green leaves. Although it looks a lot like a cabbage or a turnip, it has a sweeter, milder flavor.
It has impressive yields, too – you only need to plant about four or five plants per each member of your household.
Although it looks odd, kohlrabi has a delicious flavor and is incredibly versatile, since you can eat both the leaves and the tubers. It’s rich in fiber and in vitamin C. it also grows quickly, even in cold weather, with plants that can be harvested just a few weeks after you have planted them.
Types of Kohlrabi
There are dozens of types of kohlrabi you can grow – more than 22 varieties, in fact. These all differ in terms of their color, size, resistance, growth rate, flavor, and hardiness, too. There are some varieties that even offer exceptional storage characteristics, as well as heirlooms, hybrids, and open-pollinated varieties. There are even slow-to-bolt varieties of kohlrabi that are ideal for warm-weather growers!
With so many choices, it can be tough to narrow down which kind you want to grow in your garden – why not select a few?
If you’re looking for a disease-resistant variety, you may want to go with Gigante, which is an heirloom kohlrabi variety that also stores exceptionally well.
Another disease-resistant kind of kohlrabi plant is Early White Vienna. My personal favorite, this cultivar has a flattened stem and bolts slowly.
If you want to grow a beautiful purple kohlrabi cultivar, you might want to go with Rapid, Purple Vienna, or Kolibri. Many growers believe that the purple varieties are more resistant to certain pests, like cabbage worms, for whatever reason.
Some other popular kohlrabi varieties include:
|Early White Delicacy||Quickstar|
|Tian Tsin Strain||Axu Star|
Starting Kohlrabi from Seed
You can start your seeds outside after the danger of a frost has passed – it can tolerate a light frost, but not a hard freeze, so keep that in mind. If you want a fall crop, plant in the midsummer, but if you’d prefer a spring crop, start as soon as the risk of a hard freeze has passed.
You can also start seeds indoors. Kohlrabi is a hardy biennial usually grown as an annual. Most people will sow kohlrabi seeds directly in the garden about three to four weeks before the last frost date in the spring.
It grows best in cool temperatures, ideally those between 40 and 75 degrees F (4 to 23 C). It only needs about 60 days, at most, to reach maturity, so you don’t have to worry about it taking too long to harvest it. It can even handle an early fall frost.
Sow your seeds about half an inch deep and one inch apart, then thin the seedlings to about five inches apart later on.
Something I love about kohlrabi is that the seedlings are so tough, you can transplant them to another spot after you’ve thinned them. You can’t do this with most kinds of plants!
Kohlrabi should be grown in full sun, ideally in rich, well-draining soil. It can be planted as a cool-season crop for harvest in the spring or in the fall, or you can grow it for a winter harvest in the south.
If you start kohlrabi from seed outdoors, you will want to thin them to about four inches apart. You can do this when they are large enough to be handled.
Plant your kohlrabi plants in full sun in wells-raining soil. Make sure the soil is organically rich before you plant – I recommend working some aged compost into the planting area before you plant your seeds or transplants.
One of my favorite things about growing kohlrabi is that it doesn’t take much effort to keep the area around your plants well-weeded. Because its top growth produces such a dense canopy, I’ve found that it does a great job of shading out most of the weeds below.
When it comes time to weed, just make sure you cultivate carefully to avoid disturbing the new roots. You can also mulch when the plants are about four inches tall.
Kohlrabi needs lots of water in order to grow quickly, and to prevent the development of woody bulbs. If you let it go for long periods of time without water, you won’t like the taste and texture of the bulbs.
Provide your plants with at least one to two inches of water during the growing season. A layer of mulch can help the soil retain moisture, particularly if you don’t have the best-draining soil.
Mulch will also help to repel weeds and keep things nice and cool, a must when you are growing kohlrabi.
Kohlrabi prefers soil that is around 5.5 to 6.8 when it comes to its pH value. You can work some aged compost into your raised beds before you plant, and then side-dress with compost or compost tea about halfway through the growing season, too. No other fertilizers are needed.
Pests and Diseases
Kohlrabi is relatively hardy and not susceptible to many common pests and diseases. The most common insect pests that will go after your kohlrabi plants include cabbage loopers, cabbage worms, and cutworms.
The most effective remedy against cutworms are collars, which you can place around the stems of the plants to protect fragile seedlings. You can also remove any egg cluster you find beneath leaves, and spray your plants with a diluted mixture of soap and water.
Bacillus thuringiensis is an effective organic remedy against many of these pests, too. A natural soil-borne organism, it will repel pests without damaging beneficial insects.
One other pest you might have to watch out for? A furry one – rabbits! Rabbits will often nibble on kohlrabi leaves. The best way to keep them out is to erect a small fence around your garden.
When it comes to diseases, the main ones to watch out for include clubroot, downy mildew, and cabbage yellows. To prevent them, rotate your crops and don’t plant kohlrabi in the same spot two growing seasons in a row.
Clean the garden at the end of each season, getting rid of all plant matter (don’t compost it – just toss it or burn it). If you notice any plants infected by these diseases, destroy them immediately, too.
Kohlrabi grows well with a large list of other plants, including herbs, celery, onions, potatoes, and beets. Although you might be able to get away with it, I wouldn’t recommend growing it near any other cole crops, like broccoli or cabbage.
You might find that the plants are susceptible to the same diseases and pests, which can prove to be problematic later in the growing season.
Many growers also advise against growing kohlrabi with plants like tomatoes, pole beans, and strawberries.
Growing Kohlrabi in Containers
If you don’t have a lot of space in the garden, you can even grow kohlrabi in containers. To do this, choose a container that is large enough to allow for proper bulb development. It sets incredibly large roots, too, so you will need to make sure the container is not just wide, but also deep.
Your container also needs to be well-draining. Make sure your container has drainage holes poked into the bottom, before you fill it with good potting soil mix. Place the container in full sun, and be sure to water it often.
Container-grown plants will dry out more quickly than those grown in the ground, so you’ll want to pay close attention to make sure the soil does not become dry to the touch. Feel free to mulch, even when you’re growing in a container!
How to Harvest Kohlrabi
Harvest your kohlrabi when the bulbs are two or three inches in diameter – anything beyond that, and they will become dense and woody. You can also harvest and eat the foliage of the plant, doing so when it is young and tender.
Some people plant kohlrabi plants in succession. This is a great idea if you want a continuous harvest from spring until fall. Plant new seeds every two to three works and you’ll have all the kohlrabi you can eat.
Knowing when to harvest your kohlrabi plants will come down to being vigilant and watching your plants for signs of maturity.
Normally, kohlrabi will mature in 50 to 70 days – at least, if you’re growing one of the more popular fast-maturing varieties. However, it might take slightly longer if you’re growing one of the later-season crops.
Either way, kohlrabi bulbs are best harvested when they are small. This is when the flavor will be at its peak. Wait too long, and you’ll likely find that the plants become tough and unpalatable.
Look for a swelling base, and once it reaches three inches in diameter, cut the bulb from the root with a knife. Position the knife at the soil level, just beneath the bulb.
You can then remove the leaves from the upper stems and wash them before you cook them. Peel the outer skin from the bulbs and then eat it raw or cook it like a turnip.
Uses for Kohlrabi
There are millions of ways you can eat kohlrabi. I like to eat the stems fresh, just like an apple, but you can also shred the bulbs or stems and eat them like salad greens, in stir-fries, boiled, steamed, sauteed, or served with some sauce as a side dish.
You can use the tops as whole salad greens or cook them up as spinach substitutes, too. The taste is a bit stronger, but overall, quite similar.
You can peel and slice kohlrabi tubers to snack on with dips, or you can cook them just like turnips. There are millions of uses for this nutritious plant!
After you’ve harvested your kohlrabi, it should be stored in the refrigerator for up to one week. You can store it in for two months if you have a cold, somewhat moist place to do so (like a root cellar).
You can also freeze kohlrabi for later use. If you freeze it, I recommend processing it first – by shredding or cubing it – so that it’s easier to work with once it’s thawed.
No matter what you decide to do with your kohlrabi harvest, you’re sure to find that it becomes a new favorite in your dinnertime rotation. There’s no plant that’s quite as well-suited for cold season growing – nor is there one that’s quite as easy to grow.
You’re sure to have all of your neighbors talking and once you know how to grow kohlrabi, you’ll include it in your garden plans each year – guaranteed.
Rebekah is a high-school English teacher n New York, where she lives on a 22 acre homestead. She raises and grows chickens, bees, and veggies such as zucchini (among other things).