How to grow kohlrabi outdoors without chemicals

Kohlrabi is the most unique cabbage variety. Its small, spherical stems are eaten, and their vitamin C content rivals that of lemon.

Getting a bountiful harvest of this healthy vegetable is quite easy, even without additional chemical treatments. Cabbage can be grown using both seedlings and non-seedling methods.

Which variety to choose?

The variety is chosen based on the desired harvest time. Early varieties are capable of producing a harvest by early summer. This cabbage can be successfully grown even in colder regions of the country. The best of these include the hybrids Vienna White, Vienna White, Zadumka, Pikant, Optimus Sinii, and Smak. Early-ripening cabbage varieties are grown primarily in greenhouses or hotbeds. Late-ripening varieties ripen three months after sowing. They are planted outdoors in midsummer to produce fresh vegetables in the fall. Late-ripening varieties include Atena, Gigant, Kossak, and Eder F1.

The variety is selected based on the soil structure. Early varieties are better suited for moderately moist loams. Late-ripening cabbage grows well in floodplain and loamy soils.

Conditions for planting cabbage and turnips

Cabbage, like other cruciferous vegetables, requires warmth, moisture, and fertile soil. It can be planted in a separate plot or as a filler for other vegetable beds, in areas rich in nitrogen. If kohlrabi has already been growing in the garden, it can be returned to its original location only after 3-4 years. Kohlrabi thrives in central Russia, as it prefers high humidity (over 75%) and moderate temperatures (18-20 degrees Celsius). It does not tolerate heat, drought, and constant rainfall—it immediately cracks, dries out, becomes woody, and loses flavor. However, kohlrabi, especially seedlings, tolerates slight temperature drops well. However, experimenting with this is not recommended—if planting early, it is better to keep the seedlings under plastic.

Features of growing kohlrabi in open ground

The crop's early maturity allows for two harvests per year with proper agricultural practices. The fastest way to harvest is from seedlings. For late ripening (fall), seeds can be sown directly into the ground or a greenhouse. The growing season is also influenced by planting time, soil fertility, fertilizing, and various care practices.

When to plant kohlrabi

Seeds for seedlings for the first summer harvest are sown in late March. Planting of the seedlings in the garden is expected to take place around the May holidays. At this time, kohlrabi seedlings have two pairs of leaves. The seedlings are 40 days old.

Seedlings can be planted outdoors in stages: in early May, then in June and July. If planted in May, the first harvest can be obtained as early as June.

The second harvest is obtained by seed. In early June, the seeds are sown directly into the garden bed. In this case, the cabbage ripens in late summer. The harvest can also be obtained in October. For this purpose, the seeds are sown for seedlings in late June.

Soil requirements

Kohlrabi isn't picky about soil, but it produces juicier and denser fruits in well-drained areas with a neutral pH (slightly acidic soil is acceptable). For lush foliage growth and large fruit, the soil should be rich in nitrogen and other elements. If the soil lacks potassium or phosphorus, the kohlrabi will grow less juicy and, consequently, with poor flavor.

Lighting

To ensure juicy and firm stems, kohlrabi is grown in sunny areas. However, this cabbage variety also thrives in shaded areas (under fruit trees, near berry bushes).

Growing cabbage from seeds

Late-ripening varieties, ripening 100 days after sowing, are suitable for direct sowing. The soil under the bed is prepared in the spring, adding humus and compost. Peat is added to loosen the soil structure, and lime is added to neutralize the acidity. The bottom of the furrows is sprinkled with wood ash. Seeds are sown individually in narrow furrows to a maximum depth of 1.5 centimeters. When sowing in strips, the distance between rows should be 30 centimeters. The interval between seeds is 10 centimeters. Sowing in dense beds is possible, but thinning the plantings will be necessary. Planting in May is the ideal time for kohlrabi, as the seedlings receive plenty of light while the sun is not yet strong. The first shoots from ground sowing appear within a week. During this time, the plantings should be protected from overnight cold spells, sudden rains, and temperature fluctuations. To do this, it is enough to cover the bed with agrofibre.

Seedling method of growing kohlrabi

You can get a harvest two weeks faster by growing seedlings. This harvest can be achieved by early summer. This method involves sowing seeds in seedling containers and then transplanting the mature seedlings into the ground. Seedlings emerge faster than when grown from seeds. However, the seedling method has one major drawback: cabbage seedlings do not respond well to transplanting due to their poorly developed root system.

Seed preparation

To prevent future rot and fungal damage to seedlings, cabbage seeds undergo pre-sowing treatment. To boost immunity, seeds are given contrast baths: 50 minutes in hot water, then 10 minutes in cold water. If you're unsure of the quality of the seeds, soak them in a growth stimulant or soak them for half an hour in a solution containing beneficial chemicals. You can also place the seeds in a moist substrate to stimulate their vital processes. When planted, these seeds will already be swollen and half-open. You can disinfect the planting material with a potassium permanganate solution.

Before planting, the seeds are dried to make them flowable.

Soil preparation

The best soil for seed germination is loose, well-aerated. This can be achieved by mixing equal parts of turf, peat, and sand. Adding a cup of ash to the soil is a good idea. Before sowing, the soil should be disinfected with potassium permanganate or baked in an oven for 30 minutes at 110 degrees Celsius.

Sowing technique

Sow the seeds in long, shallow furrows, spaced 2.5-3 centimeters apart. Because kohlrabi seeds are so small, it's difficult to plant each seed individually, so scatter the seeds in a dense cluster, distributing them with your fingers. Ideally, space the seeds at least a centimeter apart. If sowing in peat pots, place 3-4 seeds in each pot. The seeds should be no deeper than 1.5 centimeters in the soil. Sow in moist soil.

The seedbed is covered with plastic or glass, creating a greenhouse effect. For the seeds to germinate, the air in the makeshift greenhouse must be heated to 20 degrees Celsius. As soon as the seedlings emerge above the ground, the protective covering is removed and the temperature is lowered to 9 degrees Celsius. This prevents the seedlings from stretching. After 7-10 days, the temperature is increased to 15-18 degrees Celsius.

Growing seedlings

Two weeks after germination, the seedlings are given their first mineral fertilizer. When the first pair of leaves emerge, the seedlings are pricked out, transplanting the strongest shoots into larger containers. Those initially grown in individual containers are thinned out.

A week before planting the seedlings, stop watering them. Kohlrabi seedlings are planted in May, when the soil has warmed up sufficiently. A couple of weeks before planting the cabbage, you can cover the area with plastic film—this will create additional warmth in the soil layers. Don't rush planting the seedlings, as too-cold soil can cause them to bolt.

Prepare the cabbage plot in advance: add organic matter in the fall, and in the spring, add humus, superphosphate, urea, and wood ash. It's a good idea to disinfect the soil by pouring boiling water or a fungicide over it. Mature seedlings should have 5-6 leaves.

The bushes are planted densely: 35-40 centimeters between rows and 15-20 centimeters between plants. For later-season varieties, the spacing between seedlings can be slightly wider. The planting depth is until the first pair of leaves begins to grow. Cover the tops of the plants with plastic or agrofibre to help the cabbage establish itself more quickly in the new conditions and begin to grow.

Subtleties of further care

Kohlrabi is easy to grow, but it still produces good yields only with proper care. Improper growing conditions can lead to bolting and poor-quality vegetables. It's best to grow it on the southeast side of the plot—this area receives good sun during the first half of the day and is usually windless.

After planting the seedlings, compact the soil around their base and water them for the first time. To reduce evaporation, cover the wet bed with a layer of dry soil. Loosening and weeding are carried out regularly to prevent deterioration of the soil. Water the cabbage plants only with warm water. Additional thinning is carried out if necessary.

Watering and fertilizing

Although cabbage loves water, it should be watered sparingly. Otherwise, it can encourage fungus. During the first week after planting, water the bed every other day, using 200 milliliters of water per seedling. Then, increase the watering rate (up to a liter per plant), and reduce the frequency of watering to once a week. Cabbage needs water especially in mid-June, with the onset of hot weather. Kohlrabi doesn't require as much water as other cabbage varieties, but it's still important to avoid allowing the soil to dry out, as this will affect the quality of the fruit.

Watering is combined with fertilizing. Fertilizers are applied 3-4 times during the growing season, at two-week intervals. The first application is done after transplanting, using micronutrient solutions. The next application is done at planting. This time, a solution of chicken manure or rotted manure is added to the soil. Mineral fertilizers are then added again. Before planting, additional foliar spraying can be done with a mixture of potassium sulfate (one tablespoon) and urea (one tablespoon) per 10 liters of water.

Loosening and hilling

These two simple techniques are essential for growing kohlrabi, but they must be used with caution, as the plant's root system is close to the surface and very weak. Loosening the soil is done a few hours after watering, preferably in the evening. Under young seedlings, loosen the soil to a depth of about a centimeter; for mature plants, loosen the soil to a depth of about 5 centimeters. A couple of weeks after planting, hilling up the seedlings is done. Raking soil onto the lower leaves stimulates root growth, strengthening the plant. Hilling up the cabbage again a couple of weeks after the initial procedure.

Protection from diseases and pests

Kohlrabi is susceptible to the same diseases that affect cruciferous plants. The main diseases include:

• keel;
• black leg;
• bacteriosis;
• downy mildew;
• dry rot;
• mosaic and others.

Following basic agricultural practices will help prevent infection in your cabbage bed:

• compliance with crop rotation;
• seed treatment before sowing;
• regular soil cultivation;
• regular clearing of the area from weeds and plant debris;
• selection of disease-resistant hybrid varieties for cultivation.

In the early stages of the disease, adjusting the growing conditions can help save plants: thinning, loosening the soil, reducing watering, and installing plastic covers (during frequent rainfall and cold snaps). If the disease is severe, use bacterial preparations (Fitosporin M). To combat blackleg, spray plants with fungicides such as Planriz, Gamair, and Alirin-B. Bactofit and Binoram are effective against bacterial diseases.

It's known that many pests harbor infections, including Alternaria blight, Phoma blight, bacterial blight, and others. Therefore, it's important to implement a comprehensive insect control program, eliminating them using all possible means.

The main threat to cabbage is posed by insects such as:

• cruciferous flea beetles;
• cabbage fly;
• snails and slugs;
• aphids, cabbage moths and cabbage whites.

Since kohlrabi reacts negatively to pesticides, only traditional methods can be used to control pathogens. Treating the soil with ash, as well as aqueous solutions containing pepper and tobacco, are effective at eliminating insects.

Harvesting and storing kohlrabi cabbage

Cabbage is ready to eat two months after sowing, when the stems reach 5-8 centimeters in diameter. Each head weighs 120-130 grams. As the stems grow too large, the cabbage becomes coarse, tasteless, and loses most of its vitamins. The stems are dug out of the ground, roots included. The lower leaves are plucked off. Kohlrabi is stored with the roots attached.

Storage boxes for cabbage are disinfected with bleach. Only whole cabbages, free of disease and mechanical defects, are allowed for storage. Cabbage is stored in a cool room at -1 to 0 degrees Celsius.

Late cabbage is suitable for long-term storage. It is harvested along with white cabbage, around the beginning of October. Late varieties such as Gigant, Violetta, and Delikatesnaya Golubaya retain their marketable qualities the longest. Purple varieties store significantly longer than green ones. Fruits harvested for long-term storage are sprinkled with damp sand – this will preserve the harvest for up to eight months. If frozen, the cabbage will keep until spring.

Tips and recommendations

1. It is strongly recommended not to water kohlrabi using the sprinkler method, as this often leads to the spread of downy mildew.
2. Plants need to be well ventilated and receive enough sun, so planting density should be maintained.
3. Before planting seedlings, the roots can be dipped in a mixture of clay and mullein with the addition of the bio-product Fitolavin.
4. Kohlrabi is completely undemanding of its neighbors. It easily grows between tomato, cucumber, and carrot rows.
5. It is advisable to plant several varieties of kohlrabi with different ripening times at once - this will allow you to have a harvest from early summer to late autumn.
6. It's not recommended to apply fresh manure to cabbage. It's better to use compost and bird droppings as organic matter.
7. The Russian climate favors growing kohlrabi primarily from seedlings. The vegetable is grown indoors in nurseries or heated greenhouses.

Conclusion

Many of our compatriots still consider kohlrabi a difficult crop to grow. However, those familiar with the intricacies of cultivating this vegetable claim that even an inexperienced gardener can grow kohlrabi. To obtain a healthy harvest, simply follow simple agricultural practices and follow the simple advice of experienced gardeners.