The A-Z of growing capsicum profitably

Sweet pepper is a widely grown. It comes in red, yellow or green varieties.

The pepper has a mild flavour and is used in stews, salads, or stuffings with meats and pickles.

The plant can tolerate many climatic conditions from warm temperate to tropical, including irrigated dry hot areas.

Capsicums are sensitive to frost and the optimum temperatures for proper growth is 15 to 25ºC. The vegetables grow well in altitudes of up to 2,000 metres above sea level.

Soil requirements for capsicums are not strict as they can grow on most well-drained loamy or heavy cracking clay soils with an optimum pH range of 6.0 to 6.5. The low night temperatures in July and August in Kenya are good for this crop.

Seeds take 12 to 21 days to germinate with optimum soil temperatures of between 13 to 21 degrees centigrade. The seedlings will last 45 days in the nursery bed before transplanting. The crop is ready for harvesting after 90 days.

To make a seedling nursery, prepare a raised bed -- a metre wide or any convenient length. Manure (20kg/m2) and phosphatic fertiliser should be used.

Seeds should be sown in drilled rows spaced 15cm and thinly covered with soil. Thinning or pricking out should be done to a final seedling spacing of 5cm to allow growth of healthy seedlings.

Seedling beds can be lightly shaded in the first two weeks of germination and seedling development and watering done twice a day if in a hot environment.

Capsicum seed rate is 0.5kg/ha in the nursery and 1kg/ha for direct sowing. The field site for establishing capsicums should be well-prepared and manure applied judiciously (10 tons/ha).

Transplanting is done when seedlings are four to six weeks old (at a height of 10 to 15cm). At a spacing of 75cm by 45cm, one acre can easily accommodate 10,000 plants. At planting, 250kg/ha of double super phosphate fertiliser should be applied.

IRRIGATION

When they reach 15cm, top-dress with 100kg/ha of nitrogen (from CAN or equivalent source) and four weeks later another 200kg/ha should be applied.
As part of horticultural management to maximise production, the growing tips can be pinched out when the plants are 3cm high to encourage branching. Capsicum will perform well under irrigation.

Harvesting starts 2.5 to three months after planting and can continue for four to six months with good management. Only mature fruits should be picked and packaged for market. Sweet peppers should be harvested when filled out and still green.

Harvested fruits should be placed under shade for grading, sorting, and packaging to avoid shrivelling. Export produce should conform to the required standards with respect to quality, packaging and labelling.

With 10,000 plants per ha, each yielding about 15 to 25 good sized marketable fruits, a total harvest of 150,000 to 250,000 fruits depending on management is possible. At a market price of Sh5 to Sh10 per fruit, the gross turnover of Sh1 million per ha is not an over-estimation as long as there is good market.

Production cost per hectare is about Sh150,000. Marketing opportunities are excellent in the local and export realms. There are several pests and diseases you must be aware of as far as capsicum growing is concerned.

Blossom-end rot: The disorder is caused by lack of calcium. It creates dark brown or black spots on immature fruits. To overcome it, plants should be evenly watered to ensure a steady flow of calcium to the fruits, especially at the forming stage.

Damping-off: Here, seedlings suddenly fall over and rot. This is caused by fungus and can be prevented by keeping the soil in which seedlings grow slightly dry to avoid excessive watering.

Cutworms: This nocturnal caterpillar curls around seedling stems and eats through them. They are controlled by using cutworm collars and applying beneficial nematodes to the soil.

Root-knot nematodes: These are microscopic soil-dwelling worms that can invade roots and make them wilt. They can be eradicated by growing a cover crop of marigolds or rye in infested fields for rotation.

Prof Mulwa is a crops expert at Egerton University.