Kohlrabi, although technically a cabbage, is more like a root vegetable. Its distinctive taste and general usefulness are unquestionable, and its wide range of uses, both on its own and as part of various dishes, as well as its unusual appearance, ensure that this type of cabbage receives genuine attention from vegetable lovers and gardeners alike. For the latter, the answers to the questions on growing kohlrabi that follow will come in handy.

Kohlrabi when to plant

Kohlrabi when to plantThe time for planting kohlrabi cabbage seeds directly depends on both the climate conditions and the type of cultivation, where it is possible to grow through seedlings or to plant directly in the open air.

On average, it can be said that in warm states, seedlings can be planted in the first half of April. In more temperate or colder climates, this time frame shifts towards the end of April, and sometimes it is better to wait until the first half of May.

Expert opinion
Jacob Johnson
Agronomist with 7 years' experiences. Bachelor of Science in Agricultural Biology - New Mexico State University
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If the seeds are to be planted outdoors, this can be done as early as the second half of May if the seedbeds can be covered with plastic sheeting. The best time to plant the seeds outdoors is after mid-June, so that cold weather and frost can be avoided for sure.

The best kohlrabi varieties for growing

When choosing a variety to plant, you need to understand the main differences between early and late varieties of kohlrabi.

kohlrabi varieties
The best kohlrabi varieties for growing

Kohlrabi varieties differ mainly in their maturity and yield, but the timing of maturity plays a particular role here, as the plant is capable of producing more than one crop per season, leading to a situation in which early varieties can produce two and sometimes three crops, while late varieties will only ripen once at the same time.

Expert opinion
Jacob Johnson
Agronomist with 7 years' experiences. Bachelor of Science in Agricultural Biology - New Mexico State University
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The yields of the varieties do not vary much; on average, kohlrabi yields between 3 and 5 kilograms per square meter.

So the question of which variety to choose depends on a time frame that suits you and also on the desired result of the crop—whether you are prepared for one impressive harvest or whether you are more comfortable with a few small ones.

Growing seedlings

Growing seedlingsGiven the difficult, sometimes harsh, weather conditions in much of the USA, it is relatively safe to say that the most suitable method of growing not only kohlrabi, but also most other crops is the sprouting method.

In the case of kohlrabi, this is the method that will produce the best early harvest and, in the case of suitable varieties, even more than one.

  • Sprouting kohlrabi can be done in several stages, using different varieties.
  • The question of growing kohlrabi can be asked starting in mid-March, when it is time to sow the early varieties.
  • By the first half of May, however, the choice of varieties becomes a secondary issue, and any variety that you like can be sown.
  • If you want the crop in the middle or even late autumn, the deadline for planting kohlrabi is the end of June, no later than the 24th or 25th.

Expert opinion
Jacob Johnson
Agronomist with 7 years' experiences. Bachelor of Science in Agricultural Biology - New Mexico State University
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In colder climates, early and medium-ripening varieties should not be planted until mid-April, and late-ripening varieties should not be planted at all, as they will not have time to mature. In southern regions, on the other hand, seedlings can be prepared as early as the beginning of February.

However, the sprouting process itself does not start with sowing and consists of the following steps:

Preparing the seeds

    Preparing the seeds

  • selection of the seeds, in which the largest and most whole seeds must be selected;
  • To disinfect the seeds, soak them in hot water (50-55 °C) for 20 minutes.The next step is to put the same seeds in cold water for a few minutes. Before proceeding further, the seeds should be washed in normal water and then dried;
  • As a final step, to give the seeds some stability, it is a good idea to put them in a cellar or in the fridge; make sure that the temperature is not too low. It is best to keep the seeds at +2°C for 24 hours.

Getting the ground and containers ready

This cabbage is not too picky when it comes to soil; the most important thing is to choose a soil that is not too dense and has a moderate acidity. You can also make your own soil by mixing sand, soil, and peat in a 1:1:1 ratio.

Preparing the soil
Preparing the soil and containers

Any wooden or plastic container, preferably oblong in shape and at least 5 cm high, will do. Immediately before planting, it is best to disinfect the soil in the container with a weak manganese solution.

Containers for sprouts
Containers for sprouts

Growing kohlrabi seedlings

  1. Make a hole in the soil about one centimeter deep, leaving a distance of 3 cm between the holes.
  2. Place the seeds at the bottom of the cavity, leaving 1.5–2 cm between the seeds;
  3. After planting, cover the furrows with soil and compact them.
  4. The container with the seedlings should be covered with a transparent bag and placed in a room with a temperature of about +20 °C and plenty of light.

growing kohlrabi in containers
Growing kohlrabi in containers

Care of seedlings

Once the seedlings have started to germinate, which will be after about 5 days, the temperature should be reduced to +10°C for a week and a half, after which the temperature should be returned to its previous level of about +20°C. As the seedlings grow, the temperature should be gradually reduced, aiming for +17°C during the day and +10°C at night.

Correctly planted seedlings need further care, which includes:

Feeding

Planting kohlrabi requires fertilization, which is carried out in three passes. For each fertilization, any nutrient mix including phosphorus, potassium, and nitrogen will do.
Feeding seedlings

  • The first fertilization should be carried out after 3–4 leaves have emerged;
  • The second fertilization should be carried out after 20–25 days;
  • The last fertilization should be carried out shortly before planting, ideally a week before moving into the garden.

Watering

When it comes to watering, it is difficult to give specific recommendations, but the general rule is to maintain optimum soil moisture, avoiding either excessive moisture or drying out the soil.

Planting kohlrabi outdoors

Planting kohlrabi outdoorsThe main marker that marks the need for transplanting into the vegetable garden is the presence of 5–6 fully developed leaves, if properly maintained, on days 35–40 after the seedlings have been planted.

Begin aerating the room with the seedlings two weeks before transplanting as final preparation for the move, gradually increasing the intervals with access to fresh air, and avoid strong draughts. During the last week, the seedlings can be taken out into the fresh air for a couple of hours.

Expert opinion
Jacob Johnson
Agronomist with 7 years' experiences. Bachelor of Science in Agricultural Biology - New Mexico State University
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For transplanting seedlings safely into the open ground, temperatures of +14 °C during the day are optimal; for northern regions, where these conditions are not present by this time, you should cover the seedlings with plastic film or plastic cups to help protect the plants from light frosts of up to -2 °C.

As mentioned earlier, kohlrabi sprouts can be carried out in several runs, according to which the move can take place on the following dates:

  • The earliest seedlings can be moved into the vegetable garden from late April to the first week of May;
  • The second seedlings are usually ready to move in by the beginning of June;
  • The latest, sown in June, are ready for transplanting by early August.

Expert opinion
Jacob Johnson
Agronomist with 7 years' experiences. Bachelor of Science in Agricultural Biology - New Mexico State University
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Any time there is no direct sunlight, it is a good time to move into the vegetable garden. If sunny weather is expected in the days following transplanting, the plants should be covered with a loose cloth or gauze for a couple of days.

Care in the vegetable garden

Like sprouts, kohlrabi already growing in the vegetable garden requires attention and care, which includes the following:

Watering

Watering kohlrabiSimilar to the care of seedlings, the more mature kohlrabi needs careful and timely watering. For the first couple of weeks after transplanting, it is better to arrange watering every 3–4 days, then water depending on the plants’ needs and conditions. It is rational to water kohlrabi once a week under normal conditions.

The watering itself, as for many other plants, should be done in the absence of direct sunlight in the afternoon or in the morning;

Loosening the soil

It can be done immediately after transplanting because it is critical for young plants to get enough oxygen and moisture through the roots. Each watering can be completed with this procedure, and the optimum depth of loosening is 17–20 inches.

Loosening the soil
Loosening the soil

Feeding

Feeding kohlrabiKohlrabi has an amazing ability to accumulate and retain nitrates, so it is important not to overdo it. The fertilizer applied at transplanting should be enough for the period of stem formation. After that, the fertilization plan is similar to the seedling plan and consists of applying general fertilizer in several approaches, distributed at regular intervals according to the period of maturity.

Sometimes this plant needs phosphorus and potassium, as indicated by underdeveloped leaves or chlorotic spots.

Growing kohlrabi in the open ground

In the American climate, this method of cultivation is relevant mainly for the southern regions. Planting kohlrabi seeds in the ground is possible beginning in late May; in this case, cover the bed for heat insulation. If we are talking about less labor-intensive planting, the optimal time is the middle of June.

Growing kohlrabi in the open ground
Growing kohlrabi in the open ground

You must also prepare the soil of your plot in the autumn preceding the planting season. The acidity of the soil should not be too high; for this, you can treat the soil with lime-lime at the rate of one kilogram per square meter. It will not be superfluous to add fertilizer to the soil, each square meter should get:

  • Ash in the amount of 150-200 grams;
  • Superphosphate, 10–15 grams;
  • Urea, 5-7 grams;
  • Muck or manure in a quantity of 3-4 kg

After fertilizing the soil, the top 20 to 25 inches of soil should be tilled.


The preparation of seeds is carried out similarly to the seedling method. Planting seeds of kohlrabi in the open ground can be done as follows:

  • The soil must be leveled beforehand;
  • Radishes are formed according to the planting pattern: 23 inches between beds and 7 inches between seeds;
  • In each row, a groove is formed for the seeds;
  • Each row is watered, preferably using a watering can with a sprinkler;
  • The seeds are placed in the groove to a depth of 2 cm, covered with soil, and compacted.

Further procedures repeat the care of seedlings and seedlings.

What can I plant next to kohlrabi?

When planting in the vegetable garden, it is important to take into account the possible effects of growing nearby plants on kohlrabi and to know what can be planted next to it and what kind of neighbors should be avoided.



You can plant it next to it:

  • Cucumbers;
  • Cereals;
  • Pumpkin;
  • Carrots;
  • Potatoes;
  • Zucchini;
  • Spinach;
  • Salad;
  • The Onion.



But the neighborhood with the following plants is better to refuse:

  • Radish;
  • Tomatoes;
  • Other cabbage types;


Potential problems

Difficulties and issues that arise in the care of kohlrabi cabbage do not have any features or exceptions and are repeated by many other types of cabbage.

The main obstacles to your healthy harvest will be pests and diseases, among them:

Diseases:

Pests

The list of pests is quite extensive and includes:


To keep these insects at bay, simply remove weeds and plant plants with strong odors (onions, coriander, garlic) nearby. You can also use specialized products.

Harvesting

Kohlrabi is ready for harvest and is considered ripe when the stem reaches a diameter of 7–10 centimeters, depending on the variety. It is important not to delay harvesting, as extra time on the bed will negatively affect the taste and usefulness of the vegetable.

Harvesting
Harvesting

Expert opinion
Jacob Johnson
Agronomist with 7 years' experiences. Bachelor of Science in Agricultural Biology - New Mexico State University
Ask an expert question
It is best to collect it on a dry day. The stem should be dug up with the root, and then it should be dried. After drying, peel the fruit from the ground, as well as cut off the leaves and roots.

Storing kohlrabi

Kohlrabi is excellent for storage in a variety of ways, from storing it fresh to pickling and freezing.

Depending on the conditions and the particular variety, for long-term storage, only late-ripening varieties are suitable.

Storing kohlrabi

Note!Under ideal storage conditions, including temperatures around 0 °C and humidity levels of 90–95%, kohlrabi cabbage can be stored for 5–8 months without fear for its safety.

Conclusions

Kohlrabi, although not the most popular among the varieties of cabbage, is still worthy of attention for many reasons, starting with taste, and ending with the amount of vitamins and minerals in its composition.

Its cultivation has a number of features and nuances, but getting a delicious and healthy kohlrabi is possible even in the harsh climates of the North, which is pleasantly surprising. As a result, kohlrabi is a tasty and useful vegetable that, in addition, can be grown more than once in one season, which will definitely arouse the interest of many garden lovers.

FAQ

Can I use a greenhouse to grow kohlrabi?

Greenhouse conditions may well be resorted to, but the precocity of this plant makes it impractical.

What kind of frost can kohlrabi withstand?

Kohlrabi can withstand short-term frosts down to -7°C for mature plants and up to -2°C for young seedlings.

Which part of the plant is suitable for eating?

The edible part of the kohlrabi is the stem, which has an oval shape.

Which method of planting is preferable?

For northern regions, seedlings are the only way, but if there is a choice, the delicate root system clearly predisposes to direct planting in the open ground.

What's the best way to store kohlrabi?

It is best to store it either in the cellar or on the balcony or in the refrigerator to keep the structure of the fruit intact.