Cabbage

The cabbage (Brassica oleracea var capitata) belongs to the family Cruciferae and is related to cauliflower, broccoli and brussel sprouts. Cabbages are grown 12 months of the year in Victoria and production is concentrated in southern districts. Cabbages are grown for both fresh market and for processing. http://agriculture.vic.gov.au/agriculture/horticulture/vegetables/vegetables-a-z/cabbage-growing

Site Selection: Cabbage can be grown in a variety of soils with high organic matter throughout the year under irrigation though it thrives best in deep well-drained loamy soils. Ensure a reliable source of water supply.

Land Preparation: Field must be thoroughly hoed or ploughed (30cm deep) and harrowed. Prepare ridges or planting beds where necessary on which seedlings may be transplanted. Incorporate well-decomposed manure.

Nursing: Seeds can be sown on seed beds, in seed trays or seed boxes. A 0.3 kg of seed is required to plant 1 ha of cabbage. Prepare seed beds at 1.2m wide and any convenient length and then level beds. Water the bed, cover with a 4cm thick layer of dry grass or sawdust and burn to sterilize the soil. Alternatively, solarize soil by covering soil with transparent plastic sheets for 5-8 weeks to sterilize the soil.

Sow seeds in drills 10cm apart. Cover beds with well dried non-seeded grass or palm fronds after sowing. After emergence, remove dry grass and provide shade over the bed. Thin out weak, malformed seedlings to avoid overcrowding. Prick out seedlings 6 to 7 days after emergence. Two weeks before planting out on the field, fertilize seedlings with NPK 15-15-15 liquid feed (Prepare solution by dissolving 5g NPK in every 1 litre of water). Apply directly to the soil. Harden seedlings 1 week before transplanting by gradually decreasing shade until at least 1 day full exposure to sunlight and/or by reducing irrigation. Control pests and diseases by applying recommended fungicides and erect insect nets over seedlings. http://mofa.gov.gh/site/?page_id=14160

 

 

Climate

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 400mm to 500mm 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.

These nylon bags are ideal for cabbages from a marketing perspective. https://www.africanfarming.com/prepare-plant-cabbage/

 

Soil, Nutrition, and Irrigation

Cabbage can be grown on a wide range of soils, but the crop is sensitive to soil acidity. The optimum pH is six to 6.5, and at pH’s greater than seven the disease club root can be prevented. Cabbage is a heavy user of nitrogen and potassium and requires frequent side-dressing. Cabbage is considered a hard crop on the land, and many growers will rotate to other crops that do not have such high fertility requirements. Cabbage is grown on mineral, sand and muck soils.

On sandy soil where there is a high water table, cabbage is irrigated by sub-surface irrigation. On deeper sands it is a perfect crop for drip irrigation since fertigation can be used. In many new fields where cabbage is grown on sandy soil, plastic mulch is being used to prevent wind damage from blowing sand particles. This will increase the use of drip irrigation. Regardless of the method used, cabbage requires about one inch of water per week. The supply of water should be even throughout the growing season to prevent cracking of the heads. http://discworld.imaginary.com/cabbage/info/climate.html

 

Varieties

Cabbages can be divided into three main groups: ball head (or roundhead), conical and the large drumhead types. There is a wide range of cultivars available with many suited for production at particular times of the year whereas others can nearly be grown year round. Red cabbages are also grown but the major production is of green cabbage.

There is a wide range of varieties and particularly for the newer cultivars, their suitability for a particular area can only be judged by growing them in the region.

Some cultivars and their appropriate production time slots include:

• Late spring to winter – Green Coronet, Kameron, Red Rookie.
• Late summer to autumn – Red Ball, Beauty, Stariha.
• Summer to winter – Grand Slam.
• Autumn to winter – Red Ranger, Neptune. Winter to spring – Ballhead, Greengold, Winterhead, Terrific.

The variety Savoy King is suited to year round production in southern production areas whereas most of the other main varieties are suited to more specific production times.

These are just some of the cultivars available but it includes most of the major varieties grown. For more information on the range of cultivars and new releases seed companies should be contacted.http://agriculture.vic.gov.au/agriculture/horticulture/vegetables/vegetables-a-z/cabbage-growing

 

Spacing and Plant Populations

Cabbage plant populations vary according to the target market for that particular crop. The ideal plant population per ha-1 for a crop destined for the bagging market would be 40 – 45 000 plants. This would produce firm heads with an average head mass of 2 – 2.5kg. For the hawker market 30 – 35 000 plants ha-1 is more suitable. This would produce larger and heavier heads with an average mass of 2.5 – 3kg. The most popular spacing for cabbage production is 50cm in the row and 60cm between the rows. A staggered planting regime is recommended to reduce competition between plants. http://www.sunshineseedlings.co.za/guidelines-tips/vegetable-guidelines/cabbage-production-guidelines/

Planting Cabbage may be planted by direct seeding or trans- planting of seedlings. If direct seeding is to be used, about 2 kg of seed per hectare may be required. Seedlings should be transplanted as soon as they reach the desired size and, only well-hardened, young, stocky plants should be used. Transplanting is done in moist soil. The soil around the roots should be firmed and irrigated as soon as possible after set- ting the seedlings. In wet areas cabbage should be planted on raised beds or ridges to reduce waterlog- ging and stem or root rot diseases. Plant populations of 40 000 to 45 000 per hectare are suggested for large-headed types while for cultivars with medium-sized heads, populations of 55 000 to 65 000 plants per hectare are said to be ideal. For baby cabbage, populations of 80 000 to 100 000 plants per hectare are recommended. It is recommended that large-headed cultivars should be planted 600 to 700 mm apart between rows and 450 mm apart within rows. Smaller-headed varieties are planted 600 mm between rows and 300 mm within rows. http://www.daff.gov.za/docs/Brochures/brochureCabbage.pdf

 

Fertilization

Fertilisation Cabbage is a heavy feeder and requires supplemental fertilisation in the form of manure or compost, nitrogen, phosphorus and potassium. Fertiliser programmes should be based on soil analyses and should be developed for each field. Cabbage requires 200 to 250 kg nitrogen per hectare. Nitrogen is supplied in split applications, where 50 % to 66 % is broadcast and ploughed in just before planting. The first application is made together with phosphorus and potassium. The remainder is side-dressed two to three weeks after transplanting and again three weeks later or applied once-off at about six weeks. If a fertiliser mixture is preferred, 1 500 kg of 2:3:2 (22) and 100 kg potassium per hectare may be broadcasted before planting. A top dressing of 300 kg LAN should be applied approximately four weeks after transplanting and again 4 weeks later if required. Cabbage also needs micronutrients for proper growth and development. The crop has a high requirement of calcium and deficiencies of this nutrient may occur on acid soils, on soils with very high potassium or on very dry soils. Foliar sprays of calcium nitrate can be used to supply calcium. Magnesium may also be deficient on acid soils, on very light soils or on soils that are very high in potassium. Spraying the plants with 5 kg magnesium per hectare can rectify the problem. Cabbage is very susceptible to molybdenum deficiency. Plants should be sprayed with 125 g of sodium- or ammonium molybdate in 500l of water per hectare as soon as signs of deficiency are noticed. The availability of molybdenum may be increased by providing enough lime prior to planting. Iron may be applied with a foliar spray with 1 % iron sulphate or chelate. The deficiency of iron is common on calcareous, alkaline soils. Manganese deficiencies are prevalent on soils with a pH of more than 5,5. A foliar spray of 5 kg per hectare of manganese sulphate or 2 to 3 kg/ha of manganese oxide is suggested as soon as symptoms of deficiency are observed. Cabbage may have boron deficiencies in areas with high rainfall. Three kilograms of Solubor are effective in controlling boron deficiency. http://www.nda.agric.za/docs/Brochures/ProdGuideCabbage.pdf

Weeding:

The crop should be kept free of weeds especially in its younger stages to avoid losses due competition from weeds; which can also be a source of pests and should be controlled at all times.http://www.letstalkagric.com/crops/cabbage-farming-information-guide-beginners

 

Pest control

Aphids (several kinds)

Cabbage is attacked by several aphids but the grey cabbage aphid (Brevicoryne brassicae) and the green peach aphid (Myzus persicae) are the most common. Damage is caused when they suck sap from the plant and contaminate the edible product. Feeding of the cabbage aphid causes a chlorosis and malformation of the leaf.

 

Diamond-black moth (Plutella xylostella)

They suck sap from tender growth, resulting in a whitish, scarred appearance. Growth and yields can be seriously reduced by heavy infestation.

 

Bagrada bug (Bagrada hilarus)

They suck sap from tender growth, resulting in a whitish, scarred appearance. Growth and yields can be seriously reduced by heavy infestation.

American bollworm (Helicoverpa armigera)

The larvae feed on the leave. They cause severe damage in the early stages of growth by destroying the growing points of the plants.

Cabbage webworm (Helula spp.)

The larvae spin a thin web over their feeding places. Damage is severe during early attacks when they destroy the growing point of the plants

Greater cabbage moth (Crocidolomia binotalis)

The larvae spin a thin web over their feeding places Damage is severe during larvae spin a thin web over their feeding places. Damage is severe during early attacks when they destroy the growing point of the plants.

Red spider mite

Red spider mites are found on the underside of leaves, where they weave a fine web. Damage is caused by sucking, resulting in a bronzing and yellowing of leaves.

Cutworm (Agrotis spp.)

Cutworms cause damage when they cut off the stems of young seedlings close to ground level.

Plusia looper (Plusia spp.)

Plusia looper feeds on the leaves and causes damage by cutting the foliage.

Thrips

Thrips tabaci is the most common species on cabbage. High populations of the insect contaminate the edible product, thus affecting its appearance or quality.

 

Nematodes

Several nematodes affect cabbage. Plants infested with nematodes are unthrifty and may become stunted. Plants may also have signs of moisture or nutrient stress.

General control measures

Control measures such as crop rotation, using resistant cultivars, using registered chemicals (information from Department of Agriculture, Forestry and Fisheries resource centre)

Disease control

Damping off (Altenaria spp., Rhizoctonia solani, Pythium spp.)

Infected seedlings wilt, turn purple and die, and often have no lateral roots.

 

Control

• Using treated seed
• Sterilising the seedbed before planting
• Removing infected plants when symptoms appear symptoms appear Sclerotonia rot or white mould (sclerotinia sclerotiorum)

The disease is favoured by cool, wet conditions and it can survive for two to three years in the soil. Above-ground parts of infected plants may be covered with a white cottony growth. The tissue beneath the mould turns soft and watery.

Control

• By crop rotation
• Planting on ridges or raised beds
• Removal and destruction of infected crop residues
• Good water management aimed at keeping the soil dry

 

 

 

Clubroot (Plasmodiophora brassicae)

The disease is soil-borne and the spores can survive for up to 20 years in the soil. It is most severe on acid soils or moderate pH soils that are poorly drained or have a high clay content. Infected plants are characterised by stunting, wilting and purpling of leaves. The roots change into a mass of large, elongated or rounded swellings or clubs. The clubs rot and form bad smelling wet masses.

Control

• By practising sanitation
• Practising crop rotation
• Grow transplants in fumigated beds
• Lime the soil

 

Fusarium wilt or cabbage yellows (Fusarium oxysporum F. conglutinans)

Fusarium wilt is more prevalent in summer and the fungus persists indefinitely in the soil. Initially the symptoms appear as yellow foliage, often mainly on one side of the plant. The leaves become distorted and gradually turn brown and drop prematurely. The vascular area also discolours.

Control

• By planting resistant cultivars planting resistant cultivars
• Growing cabbage in winter
• Planting on soils free of disease
• Soil fumigation before planting
• Practising crop rotation
• Practising sanitation

Black rot (Xanthomonas campestris)

The disease is introduced to fields in seed and its spread is very rapid under hot, rainy, windy conditions. The disease survives for three to five years in fields and in the stems of host plants.

The symptoms first appear as yellow to light brown patches at the margins of leaves and later a network of black veins develops within these areas. Affected areas turn brown and dry out and often leave a characteristic triangular-shaped lesion on the leaf margin, with one point of the triangle directed towards the midrib. Older infected leaves also drop and the vascular tissue turns brown as the bacteria move into the main veins and vascular system. Plants infected at the seedling stage may die or remain stunted.

Control

• Planting tolerant or resistant cultivars
• Using disease-free seed or seed treated with hot water
• Practising crop rotation
• Control cruciferous weeds
• Avoiding the use of sprinkler irrigation
• Increase the interval between irrigation
• Deep-ploughing of all infected plant material

 

Downy mildew (Peronospera parasitica)

Downy mildew is common in cool, humid weather. The fungus survives in debris and is spread by air-borne spores in large numbers. Infected leaves appear as if they have been lightly sprinkled with pepper. The leaves become yellow around the pepper spots. Lesions merge to cover large areas of leaves. Fine, fluffy white mould appears on the lesions on the underside of the leaf during humid conditions.

Control

• Plants should not be irrigated irrigated afte r 15:00 pm and before 10:00 am.
• Treat seedlings with fungicides.
• Fumigation of the seedbed.
• Ensure good seedbed preparation and practices to ensure aeration and drying.

 

Black leg (Phoma lingam)

Black leg is seed-borne and it can infect the whole seedbed when an infected seed germinates. The whole plant wilts when infected. White to light brown lesions with a purple to black margin develop on the stem and on leaves. The lesions have small black dots in the centre. The centre of the lesion gets woody and cracks.

Control

• Use containerised seedlings.
• Do fungicide treatment of seedbed.
• Seedbeds should be situated far from old production fields.
• Seedbed should be destroyed if leaf lesions are found.
• All cabbage material remaining in seedbeds should be removed.
• Remove of cruciferous weeds from production fields.
• All debris should be removed after harvesting.

 

Bacterial leafspot (Pseudomonas syringae pv. maculicola)

Bacterial leafspot is more severe in cool, moist weather. The symptoms initially appear as small, faint, water-soaked areas on the underside of leaves. The affected areas develop into brownish to purplish grey necrotic spots, fairly irregular after a few days. They may coalesce to form large irregularly shaped spots. The leaf becomes wrinkled and the tissue may tear when the lesions are many.

Control

• Do chemical control.
• Plant tolerant or resistant cultivars.
• Use disease-free seed or seed treated with hot water.
• Practise crop rotation.
• Avoid using sprinkler irrigation.
• Increase the interval between irrigation.
• Control Control cruciferous weeds. cruciferous weeds.
• All infected plant material should be deep-ploughed.

 

Alternaria leaf spot (Alternaria spp.)

The disease is common during cool, rainy weather. Initially, symptoms appear as small, dark areas and they rapidly enlarge to form large circular lesions that develop a bull’s-eye pattern or target spot. The lesions are dark brown during wet periods. A brown, velvety, spore-bearing growth can be noticed on the older lesions.

Control

• Use disease-free or treated seed
• Removal or ploughing in plant refuse
• Chemical control http://www.nda.agric.za/docs/Brochures/ProdGuideCabbage.pdf