The market for cabbage is wide open as demand for this popular item of fresh produce grows steadily off a high platform. Large-scale commercial farmers often plant a land to cabbages because it can generate cash. What brings in money for the bigger farmers, can bring it in for smaller farmers.
Cabbage is a cool season crop and it can be difficult for inexperienced farmers to grow during the hot months, when there are more insects around to attack the crop.
Cabbage grows in almost all types of soil. It thrives in well-drained, fertile soil rich in organic matter. Crop scientists recommend a pH of between 6.5 to 7.
Although it prefers cool, humid weather, you can grow cabbage year round as long as you plant the right cultivars. It can survive temperatures below 0°C but grows optimally in the range between 15°C and 20°C.
High temperatures and low moisture levels can result in small plants and a low yield. If temperatures are too low during the growing period, the stems will grow out and the plant will bolt (form the flower stalk).
Cabbage needs about 400 mm to 500 mm of rainfall depending on the climate and length of growing season. Crop water use increases during the growing period with a peak towards the end of the season.
Contact the seed companies and choose the cultivar that suits the climate in your area. These cultivars will be in demand locally.
Cultivars and planting times: Hercules and Tenacity, plant in summer and spring. Conquistador and Gladiator, autumn and spring. Conquistador is an easy-to-grow hybrid with a large, firm head.
Rotate cabbages with tomatoes, pumpkins, sweet potatoes, beans, peas, potatoes or maize. It is a good idea to rotate with legumes like beans and peas because they can fix nitrogen and make it available in the soil. Maize is also a good crop in the rotation because of the production of organic material.
Sow seed in a nursery and transplant 3 to 4 weeks later into a fine seedbed. Make shallow furrows 15 cm apart and a finger nail deep and sow the seeds 5 cm apart in the row. Cover lightly and compress with your hand.
Mulch with dry grass on top of the seed bed to stop it from drying out. Water every day during cooler weather and twice a day if it’s hot and dry. Take the grass off five days after seedling emergence. Seedlings should be ready 4 to 6 weeks later.
Irrigate the land before you transplant when the plants are about 10 cm high. Transplant during the cooler times of the day into prepared holes. Once they are in, press down firmly and tamp down the soil around the plant.
The transplants can be hardened off before planting, gradually exposing them to field conditions to reduce transplanting shock. Transplant only healthy seedlings with good growth points and discard any that look weak, leggy or unhealthy.
The planting distance depends on the cabbage and the target market. Varieties with big heads need more space than the smaller varieties.
Small head cultivars plant 30 cm apart in the row with 50 cm between rows.
Big head varieties plant 50 cm apart in the row and 70 cm between the rows.
Cabbage is a heavy feeder and does well fed with manure, compost and organic fertilisers. For the right fertiliser application, analyse the soil. The general recommendation is to dig in 2:3:4 at 60 g to 90 g per m² – this would be the minimum amount needed to make sure the plants get a good start.
About 1 200 kg of 2:3:4 per ha is optimal. The plants respond well to a top dressing of nitrogen LAN 28% N at two, 4 and 6 weeks after transplanting. Start with 4 g per plant and increase to 10 g per plant.
Spread it about 20 cm around the plant. Don’t apply the top dressing too late, when the cabbages are already forming heads, because it can cause splitting or the development of too many leaves which results in poor or loose head formation.
Don’t get the fertiliser on the cabbage plant.
It is critical for cabbages to have water immediately after sowing or transplanting. Young plants need enough water for growth before they form heads. The bigger the plant is at this stage, the larger the eventual head will be. About 35 mm a week is optimal.
Too much water after the heads have formed, can cause them to crack which you do not want. Cracking can also happen when the crop gets water inconsistently.
Weed once the plants are established and carry on with weeding until the cabbage leaves cover the ground. Don’t damage the roots when you weed mechanically. Irrigate during the growing period and mulch to conserve moisture.
Incorporate crop residues into the soil immediately after harvesting.
PESTS AND DISEASES
Various pests and diseases that attack cabbage can lead to serious economic losses. Cabbage farmers can use Integrated Pest Management (IPM) strategies, including scouting, crop rotation, good management and chemical and mechanical controls.