Scientific name: Capsicum annuum
Common names: bell pepper, sweet pepper
Sweet peppers, also called bell peppers and even some chilli peppers all belong to the species Capsicum annuum. Cultivars of these plants produce fruits in many different colours and shapes. Usually the colours range from red to yellow and orange, but more exotic colours include purple, white and lime green. The fruit is also frequently consumed in its unripe form, when the fruit is still green. Most sweet peppers are bell-shaped, therefore the name bell pepper is common. However, sweet peppers come in a range of shapes from round to oblong, to tapered. The skin is smooth and shiny and can be a range of colours. Most peppers are green when immature, and red if allowed to ripen. However, new cultivars offer both mature and immature peppers in red, yellow, orange, purple, or brown.
Cultivars
Kinds that are frequently grown are varieties of C. frutescens, which are the peppers grown in the vegetable garden and include those from which red pepper, cayenne pepper, tabasco and paprika are made. There are many varieties of garden peppers. They are divided into two groups; the sweet peppers or mild-flavoured varieties, which are used for stuffing, salads and garnishing; and the hot peppers, which are mainly used in sauces and flavouring. The Spanish word “Chili” describes peppers of all kinds, but in English, the name is usually only applied to the pungent varieties used for flavouring. C. frutescens grossum, the sweet or bell pepper, is a popular vegetable. Certain types of peppers are very pretty when grown as potted plants, especially in the fall and early winter. The best are C. frutescens cerasiforme, the cherry pepper and C. frutescens conoides, the cone pepper. The varieties of these kinds have red, purple or cream-coloured fruit displayed above the rich green foliage. Cultivar selection Bell pepper cultivars differ in such horticultural traits as fruit size, shape (e.g. blocky versus elongated), number of lobes, flavour, and disease re specialty bell peppers include cultivars that ripen to a colour other than red. These specialty bells may be yellow, orange, brown, white, and even purple at maturity. Compared to green bell peppers, coloured bells are often more difficult and expensive to produce because a longer time to reach maturity is required. Growers should only select adapted varieties that have the qualities in demand for the intended market. Owing to the prevalence of bacterial leaf spot in Kentucky, only hybrid varieties with leaf spot resistance are recommended for commercial production. While resistance to bacterial leaf spot has helped reduce losses because of this devastating disease, new races of the pathogen have been isolated to which there is currently no resistance.
CLIMATIC REQUIREMENTS
Temperature and Humidity
Climate is one of the most important factors when determining planting times. Production of a pepper crop depends on the length of a growing season with optimal temperatures. The plant itself stops growing at temperatures below 10° - 12°C, and at 6°C, the leaves can die and flower abortion will start. The same will happen when temperatures increase to over 35°C. A pepper crop requires very stable temperature ranges with minimums and maximums not being too far apart. Temperature variation might result in poor fruit quality or reduced yields.
Optimum temperatures would be
Day time: 25 - 28°C
Night time: 16 - 18°C
This would also be the ideal temperatures for growing under protection. Long periods of overcast weather can also result in poor fruit set and loss of a crop. Hot peppers can withstand higher temperatures than sweet peppers. For the development of the pepper plant, a relative humidity between 65 – 85% is considered optimal. High relative humidity levels negatively influence pollen release and distribution on the stigma. High humidity creates a favourable environment for the development of several foliar diseases. Conversely, low relative humidity may cause infertility, due to pollen drying out before germination of the pollen on the stigma, which leads to small, deformed or flat fruit. At relatively low humidity and high temperature, evaporation rate from the leaves is rapid. If the root system is unable to supply the water volume required, it may lead to partial wilting of the growth tip and increase the incidence of blossom end rot.
SOIL REQUIREMENTS
Site and soil
Bell peppers prefer deep, fertile, well-drained soils. Avoid planting in low-lying fields next to streams and rivers because these sites are subject to high humidity and moisture conditions and, therefore, especially prone to bacterial spot epidemics. Producers should also avoid fields where long residual corn or soya bean herbicides have been used, because herbicide carry-over can cause serious damage to peppers. Pepper fields should be located as far away from tobacco plantings as possible owing to potential spread of aphid-vectored viruses from tobacco to peppers. It is also advisable not to grow peppers after other solanaceous crops (such as tobacco, tomatoes, potatoes, and brinjals) or vine crops for a period of three years because all of these crops are susceptible to some of the same diseases. Peppers do extremely well following fescue sod. Use a soil test to determine fertiliser and liming requirements. Peppers grow best at soil pH between 6,0 and 7,0. Adjust the soil pH to near neutral (7,0) for maximum yields. To reduce the risk of verticillium wilt and other diseases, avoid using fields in your rotation plans in which eggplant, tomato, pepper, potato and strawberry or cranberry have been planted.
SOIL PREPARATION
Soil preparation improves the potential for profitable production of peppers. Any primary soil preparation must be aimed at creating growing conditions for pepper plants to develop the optimal root system in a specific soil profile. The highest percentage roots will be found in the top 600 mm of the soil.
The advantages of soil preparation are:
No restrictions on root development.
Less chance of compaction.
More oxygen in the soil creating better root development.
Higher yield.
Reduction in production costs.
More vegetative growth.
More tolerance to drought and stress.
Less root disease prevalence.
Horizontal and vertical compaction layers broken.
Better water retention.
Increased uptake of moisture and nutrients.
The choice of preparation systems should be determined by the plant requirements and the soil type. Thereafter, economic factors should be considered. No standard system can be recommended on all soil types. The choice of preparation method should be made based on the clay content of the soil. For example, on sandy soils the focus should be to reduce compaction and erosion, where on heavier soils it will be to reduce crust formation. Soil preparation should be done to depths varying between 300 – 600mm. Ridging is highly recommended, and should be done according to the land contours. The main advantage of ridging a pepper crop is to keep excess water away from the plant, improved oxygenation of the root zone, increased soil depth in the growing bed, to promote root development and keep root diseases at bay. More important than fallowing in particular rotation over many years is the precaution to avoid growing peppers on the same soil more often than once in 3 or 4 years. As tomatoes and peppers are subject to some of the same diseases, neither should follow the other in successive seasons in the same soil. Soil used for plant beds should have had no peppers grown in it for 4 or 5 years, preferably never before.
Planting
Planting period
Greenhouse peppers are sown in October through February and harvest of red fruit approximately five months later, March through July.
Spacing
Although much of the greater part of the total area of all kinds of peppers is grown from transplants, seed is also sown directly in place in the open field, principally in some of the warmest parts of the country. Ten to 12 seeds can be planted 45 cm apart on rows that are 75 cm apart and later thinned when 8 to 10 cm tall to 2 plants per stand. The costs of production by sowing in place are nearly the same as by transplanting, because of the costs for much more seed, thinning and additional cultivation to control weeds. Sowing in place is not generally recommended, even in places where the season is long enough to permit its use. The seedbed for raising seedlings is made 120 to 150 cm wide and as long as necessary. The soil is pulverised by forking and breaking up the clods and removing stones and straw.
Seeding rate
One hectare requires 100 to 200 g of seeds.
Fertilisation
Recommendations for supplemental organic matter, fertiliser, lime and manure should be based on a soil test and a nutrient management plan. Nutrient management plans balance the crop requirements and nutrient availability, with the aim to optimise crop yield and minimise ground-water contamination, while improving soil productivity.
Field fertilisation
A soil test is the most accurate guide to fertiliser requirements. The following recommendations are general guidelines for loamy soils or when organic matter exceeds 2,5%. The fertiliser programme for sweet pepper production depends on the type of soil, the nutrient status and the pH of the soil. It is therefore important to analyse the soil before planting to determine any nutrient deficiency or imbalances. Phosphorus is applied before planting while potassium fertilisers are usually applied at planting time. Sweet pepper is sensitive to calcium deficiency, which normally results in blossom end rot. The crop is also sensitive to deficiency of micronutrients such as zinc, manganese, iron, boron and molybdenum.
Weed control
Good weed control in peppers begins similarly to any other crop, before the crop is planted. Control established perennials before planning to plant peppers in the field. Use cultural, mechanical and chemical weed control techniques in a coordinated manner to reduce the risk of interference with the crop. Plastic and organic mulches control weeds effectively. Higher density plant spacing will also smother weeds. Shallow cultivation will help to avoid root damage especially around young plants. Annual and perennial weeds such as ragweed, lambsquarters, redroot pigweed, galinsoga, nightshade species, yellow nutsedge, annual and perennial grasses, mustards and others, are a problem throughout the growing season. Weeds growing up through the planting holes of plastic mulch can be a particular problem.
Pest control
Aphids, European corn borer, Mites, Thrips
Disease control
Bacterial leaf spot (Xanthomonas campestris pv. vesicatoria), Phytophthora blight (Phytophthora capsici), Powdery mildew, Damping-off caused by Rhizoctonia solani and certain Pythium species, Bacterial wilt is caused by Pseudomonas solanacearum, Bacterial soft rot and Tobacco mosaic virus.
HARVESTING
Factors such as nutrients, climate, temperatures, management and logistics play an important role in the general holding ability of peppers. New generation peppers varieties have been developed, due to breeding efforts over a period of years, to possess better firmness, holding ability and shelf life. All this is useless information if a crop of peppers is not picked at the right stage, distances to the markets are not taken into consideration and the cold chain is broken (constant temperature range in which the crop is transported to its destiny). The farmer must always bear in mind that quality is profitability. The qualities that attention should be paid to include: pack-out, uniformity, fruit shape, ripening ability, firmness and flavour. The specific characteristic required will depend on the market requirements, as dictated by the packer, shipper, wholesaler, retailer and consumer.
Green Stage:
The pepper fruit is still green and when picked at this stage, will most probably last up to a maximum of two weeks in cold storage. Internally and externally fruits are very hard and crispy. This is the main segment in which the product is marketed.
Colour Breaker Stage:
These are the stages just before the pepper turns to its full genetic colour. Internally the pepper has already started to colour. On the outside one could clearly see blotches of the green fruit starting to colour. In South Africa this is the most common stage to pick coloured peppers as some farms are far away from the national markets. Fruit colouring to the full ripe stage will happen during the transportation process, or if temperatures are low it will colour on the market. Colouring of the fruit will start around the side mostly exposed to the sun. Fruit at this stage should be stored at 16-21°C.
Ripe to Full Ripe Stage:
Worldwide this is the stage where consumers buy coloured peppers. This stage gives the best colour and taste. Potentially this is the stage where the highest sugar content could be expected. This is measured with a refractometer and is expressed as brix %. Fruit at this stage should be stored at 13-18°C and 90 – 95% relative humidity. At this stage of ripening one can expect 6 % brix. Peppers are sensitive to cold and should not be stored below 13°C.Peppers are sensitive to ethylene and should not be stored with fruit that produce ethylene, such as bananas, avocados, and kiwi fruit.
