About Brassica oleracea L. var. caulorapa DC.
Brassica oleracea L. var. caulorapa DC. is a type of plant that belongs to the Brassicaceae family. It is commonly known as the Kohlrabi, German turnip, or turnip cabbage. The Kohlrabi originates from the Mediterranean region and was first cultivated in Europe in the early 16th century.
Appearance
The Kohlrabi is a unique vegetable with a bulbous shape, measuring about 2-4 inches in diameter. The bulbous stem is usually purple, although green and white varieties are also available. The stem is topped with blue-green leaves that form a rosette pattern. The leaves are similar to those of the cabbage plant and are edible, but they are often discarded in most recipes.
Uses
Kohlrabi is a multi-purpose vegetable that is used in various culinary dishes around the world. The taste of the Kohlrabi is similar to the taste of the broccoli stem, with a hint of mild sweetness. Therefore, it can be eaten raw or cooked. The bulb is often used in salads, coleslaws, soups, stews, and even pickled. The leaves are also edible and can be used to wrap food, add flavor to soups, or juiced.
Aside from being a tasty addition to most dishes, Kohlrabi offers an array of health benefits. It is a great source of dietary fiber, vitamins, and minerals, including Vitamin C, potassium, and calcium. Regular consumption of Kohlrabi is also believed to help maintain healthy digestion, boost immunity, and potentially reduce inflammation in the body.
Light Requirements
Brassica oleracea L. var. caulorapa DC. prefers full sunlight exposure for optimal growth. About 6-8 hours of direct sunlight a day is recommended for this plant to thrive.
Temperature Requirements
The ideal temperature range for Brassica oleracea L. var. caulorapa DC. falls between 60-65°F (15.5-18.5°C) at night and 75-80°F (23.5-26.5°C) during the day. It is essential to keep the temperature consistent for a healthy crop.
Soil Requirements
The plant grows best in well-drained soil with a pH range between 6.5-7.5. The soil should be rich in organic matter and should be kept consistently moist. It is important to avoid waterlogging the soil as this can cause root rot and stunted growth.
Cultivation Methods
Brassica oleracea L. var. caulorapa DC. or simply kohlrabi is a cool season vegetable that grows best in well-draining soil with a pH level of 6.5 to 6.8. It requires a minimum temperature of 45°F (7°C) for germination and grows best at temperatures between 60-65°F (16-18°C). Kohlrabi seeds should be sown directly in the garden bed, at least an inch deep, in rows 18-24 inches apart, and thinned to 4-6 inches apart.
Watering Needs
Kohlrabi plants need a consistent supply of water, especially during their early growth stages. It is recommended to water the plants at least 1 to 1.5 inches per week, depending on the weather conditions. The soil should remain moist but not waterlogged, which can lead to root rot or other fungal diseases. Mulching around the plants can help retain moisture in the soil.
Fertilization
Kohlrabi plants require a balanced fertilizer, with higher levels of nitrogen during the early growth stages. A soil test can help determine the exact nutrient requirements of your plants. Fertilizer should be applied before planting and again as the plants grow, following the recommended dosage. Over-fertilizing can harm the plants.
Pruning
Kohlrabi plants generally do not require pruning. However, they can benefit from thinning, which involves removing the extra plants from a row to provide sufficient space for the remaining plants to grow. Thinning should be done when the plants are a few inches tall and can be used as baby greens.
Propagation of Brassica oleracea L. var. caulorapa DC.
Brassica oleracea L. var. caulorapa DC., commonly known as Kohlrabi, can be propagated through various methods. These methods include:
Seed Propagation
One of the most common ways of propagating Kohlrabi is through seed propagation. The seeds of Kohlrabi can be sown directly into the ground or in seed trays for transplanting later. Kohlrabi seeds generally take around 7-10 days to germinate at temperatures around 10-30°C.
Vegetative Propagation
Vegetative propagation of Kohlrabi can be done through cuttings or root division. Cuttings are taken from the stem of mature plants and planted in a rooting medium. Root division involves separating the root system of mature plants into smaller pieces and planting them in suitable soil.
Air Layering
Air layering is a propagation technique that involves creating a small wound on the stem of a mature plant and then wrapping it with moist sphagnum moss and plastic wrap. Roots will form at the wound, and once they have established, the stem is cut from the parent plant and planted in suitable soil.
Overall, Kohlrabi can be propagated using various methods, making it a versatile plant to grow. The appropriate propagation method chosen will depend on the individual grower's circumstances and requirements.
Disease and Pest Management for Brassica oleracea L. var. caulorapa DC.
Brassica oleracea L. var. caulorapa DC., also known as kohlrabi, is a vegetable crop that is popular for its edible bulbous stem. To ensure healthy plants and good quality produce, it is essential to implement appropriate disease and pest management strategies. Here are some common problems and their management options:
Common Diseases:
1. Clubroot: This soil-borne disease is caused by Plasmodiophora brassicae. The symptoms include stunted growth, yellowing of leaves, and the development of swollen roots or galls. To control clubroot, ensure appropriate soil pH (6.5-7), use resistant varieties, practice crop rotation, and avoid waterlogging. Also, sterilize gardening equipment and dispose of infected plant residues properly.
2. Downy Mildew: This disease is caused by Peronospora parasitica. The symptoms include grayish white patches on both surfaces of the leaves and stunted growth. Proper management strategies include planting resistant varieties, providing good air circulation, and avoiding overhead irrigation.
3. White Rust: Caused by Albugo candida, this disease shows symptoms such as white blisters on the undersurface of leaves and yellowing as the condition becomes severe. The best way to control white rust is by planting resistant varieties and avoiding overhead watering.
Common Pests:
1. Cabbage caterpillar: The larvae of the cabbage butterfly (Pieris rapae) feed on the leaves, causing significant damage. To control the pest, handpicking or the use of bacterial insecticides such as Bacillus thuringiensis can be beneficial.
2. Aphids: These small insects feed on the sap of the plants and cause wilting and stunted growth. Control aphids by spraying the plant with a stream of water, releasing natural predators, such as ladybugs or lacewings, or by using insecticidal soap.
3. Root-knot nematodes: These pests attack the roots, causing swelling and deformation. Control options include crop rotation with non-brassica crops, use of nematode-resistant cultivars, and solarizing the soil to kill the pests.
Implementing appropriate disease and pest management strategies can help to prevent significant crop losses and maintain healthy, vigorous plants. It is essential to identify the problem at the earliest stage to prevent the spread of infection and minimize the damage.
