Black pepper: the king of spices and how to grow it

Everyone knows the small, black, wrinkled grains in the spice jar. Far fewer know that black pepper is the dried fruit of a climbing vine, one that can scramble several times a person's height up a tree or pole. Called the king of spices, it is more than a source of heat and flavour: it carries real nutritional value and, as a crop, real economic promise. Demand for it is strong at home and across world markets.

Black pepper is native to the forests of the Western Ghats and the Malabar Coast of southern India. From there, centuries ago, it travelled to the markets of Arabia, Europe and the rest of Asia, and was once so costly it was called black gold. Today Vietnam, Indonesia, India, Brazil, Malaysia, Sri Lanka and Thailand are among its major producers.

Pepper also has familiar relatives. Betel leaf, long pepper and chui jhal, the stem spice popular around Khulna, all belong to the same genus. Just as a betel vine climbs a tree or bamboo frame, a pepper vine puts out small roots from its nodes that grip its support as it climbs. Anyone who has seen betel or chui jhal grown will find pepper cultivation far from strange.

In Bangladesh, pepper is still grown on a very small scale. A report by the Agriculture Information Service (AIS), the government's farm information agency, put the national area in 2015-16 at just 5 hectares, producing 6 tonnes. Almost all the pepper sold in the country's markets is therefore imported. There are vines in homesteads and gardens, but commercial growing is only beginning.

Yet parts of the country have a climate well suited to the crop. According to AIS, pepper is grown in Sylhet, Chattogram and the Chittagong Hill Tracts, and the districts of Habiganj, Moulvibazar, Khagrachari, Rangamati and Bandarban are especially suitable. In 1987 the Bangladesh Agricultural Research Institute (BARI) selected a variety from Jaintia pepper and released it as BARI Golmorich-1, still the country's only released variety. Local types are also grown. The room to cut imports is large.

Peppercorns contain protein, fat and a good deal of carotene, calcium and iron. The original article describes pepper as rich in vitamins C, K and A and a good source of calcium, magnesium and iron, with anti-inflammatory and antibacterial properties. It is worth remembering that we eat pepper in very small amounts, so its nutritional contribution is small in proportion.

Pepper's bite comes from a compound called piperine. The health benefits attributed to it, in popular belief and in the original article, include:

• Better digestion: the piperine in pepper helps the digestive process.
• Help with weight: it is thought to raise the metabolic rate and help the body burn fat.
• Immunity: its antioxidants play a part in the body's defences.
• Skin care: it is said to improve skin health and reduce acne.
• Relief for the airways: pepper has long been a household remedy for colds, coughs and sinus trouble.

Folk medicine credits pepper with more. It is said to aid digestion, strengthen the nerves, ease toothache, soothe aching muscles and joints, and relieve constipation. These uses come from generations of experience. Still, pepper is no substitute for medicine, and a persistent complaint calls for a doctor.

Its place in the kitchen needs no introduction: meat, eggs, soups, salads and even tea. The same vine gives both black and white pepper, depending on processing. Whole berries dried in their skins become black pepper; ripe berries with the outer skin removed and the inner seed dried become white pepper.

White pepper is milder and paler, which is why cooks favour it for white sauces and light-coloured dishes. Fresh green berries go into pickles and fresh cooking. One vine, in other words, can yield three different products, depending on what the market wants.

Pepper is a crop of warm, humid climates. It thrives where rain is plentiful and the air stays moist, doing best with 100 to 200 centimetres of rain a year. The vine tolerates temperatures from 10 to 40 degrees Celsius.

Loam rich in organic matter suits it best. A soil pH of 5.5 to 6.5 is generally ideal, though it can also be grown on acid soils of pH 4.5 to 6.0. pH measures how acid or alkaline soil is; anything below 7 is acid. Hill soils suit pepper well, since they are usually acidic and water does not stand on sloping ground.

Standing water is pepper's worst enemy. Waterlogged roots bring foot rot, which can kill the whole vine, so on flat land good drainage is essential.

Along with local types, BARI Golmorich-1 can be grown. Planting material should come from good mother vines of an improved variety. Pepper is normally propagated not from seed but from cuttings of the vine, which keep the mother plant's qualities exactly. AIS advises taking cuttings in February and March from healthy mother plants, each with at least two or three nodes, or buds. Kept in shade and watered regularly, they root within a month.

Being a climber, pepper needs a pole or a living tree to grow up. Mango, jackfruit and areca nut trees can all serve. No extra land is needed: an old tree in the homestead or orchard becomes the pepper's support. Training vines up the palms of an areca nut garden is a sound form of mixed cropping in many areas.

Plants are spaced 2 to 3 metres apart. For larger commercial gardens, AIS recommends 4 metres between plants and 5 metres between rows, with pits 50 centimetres long, wide and deep. The best time to plant is the start of the monsoon, when the soil is moist and the air humid. Cuttings go in at the foot of the support so the vine has something to climb as soon as it starts to grow.

On pit preparation, the Bangladesh Agro-Meteorological Information Service (BAMIS) advises digging pits half a metre long, wide and deep, mixing in about 10 kilos of organic manure along with the necessary chemical fertiliser and bone meal, and leaving them for a while before planting. BAMIS gives Baishakh and Jyoishtha, roughly May to June, as the planting time, matching the start of the monsoon. With light shade and regular watering for the first few weeks, cuttings soon take hold.

Pepper is a perennial crop, so its feeding is planned year by year. In general it needs compost or other organic manure plus chemical fertiliser supplying potassium and phosphorus. For a mature vine, each pit receives per year:

• Urea: 300 g
• TSP (triple superphosphate): 110 g
• MoP (muriate of potash): 450 g
• Rotted cow dung: 10 kg, every year in May to June
• Lime: 600 g, every other year

The full chemical dose applies from the third year. In the first year a vine gets a third of it, and in the second year two-thirds, so the feed rises as the plant grows. Fertiliser is normally given in two splits a year: once in May to June and again in August to September.

The lime has a purpose. In high-rainfall areas soil grows more acidic over time, and lime every other year keeps acidity in check so the plant can take up nutrients properly. The generous potash dose is there because potassium strengthens the plant's resistance to disease and improves the quality of the fruit.

Pepper needs regular watering, but water must never be allowed to stand. When the soil dries out, especially in the dry season, irrigate. Clear weeds around the base as they appear, because they compete for nutrients and water.

As the shoots grow, tie them to the support so the vine does not hang down or sprawl on the ground. Regular pruning keeps growth in check, lets light and air into the canopy, keeps the harvest within reach, and reduces some pest attacks, as described below.

Pepper's most damaging pest is the flea beetle, a small beetle that can destroy 30 to 40 per cent of the crop. It must be dealt with as soon as it is seen.

The adult beetle has black wing covers, with a yellowish-brown head and thorax. Both adults and larvae eat the tender parts of the plant. The adult bores into the fruit and feeds inside; infested berries turn yellow and then black. The larva bores into the seed and eats it from within.

Shade favours the pest. Its life cycle shows why timing matters. In July the female lays one or two eggs in each young berry, about 100 in all. Larvae hatch in 5 to 8 days, and after 20 to 32 days turn into pupae. Adults emerge 6 to 7 days later and live for 39 to 50 days.

Control starts with regular pruning to cut back excess growth and reduce shade. Where needed, an approved insecticide should be applied. The Bangladesh Agro-Meteorological Information Service (BAMIS) advises spraying a cypermethrin-based insecticide two or three times at intervals of 10 to 12 days. Before using any pesticide, it is wise to consult the upazila agriculture office and follow the label.

Pepper vines can suffer leaf blight, foot rot and insect attack. The first line of defence is good drainage to prevent rot; the second is acting in time.

Two diseases are common while plants are still in the nursery: leaf rot and wilt. Leaf rot leaves black spots on the leaves; wilt makes the cuttings droop. Spraying the fungicide Bavistin or copper oxychloride at 20 grams per 10 litres of water, three times at intervals of 10 to 12 days, brings them under control.

The most feared disease of field vines is sudden, or quick, wilt. It is one of the major problems in pepper-growing regions around the world and is generally blamed on a soil-borne organism called Phytophthora. Its signs are:

• Black spots appear on the leaves and then spread.
• Young leaves and shoot tips turn black; in a heavy attack the plant dies.
• The infection can spread to every part of the plant, including the base.
• If it strikes at the end of the monsoon, the vine may yellow and collapse.

Control follows five steps: pull out infected plants with their soil and destroy them; use disease-free cuttings; avoid wounding the roots during cultivation; do not let suckers, the shoots that run along the ground, grow into the soil; and apply copper oxychloride at 0.2 per cent, which means 2 grams per litre of water.

The warning about root wounds matters. Soil organisms usually enter a plant through a wound, so hoeing too close to the base while weeding or loosening soil is a mistake. Likewise, shoots trailing on the ground invite infection from the soil, so they should be lifted and tied, or cut away.

Pepper vines begin bearing within two to three years of planting. They flower in May and June, and the fruit is ready six to eight months later. AIS gives the Bengali months of Poush and Magh, roughly December and January, as the right time to pick.

The berries grow in long, hanging spikes. When one or two berries in a spike turn bright orange or purplish red, the whole spike is picked. The berries are stripped and dried in the sun for 7 to 10 days, shrivelling from green to black: the black pepper of the market. AIS advises dipping the berries briefly in hot water before drying to keep their colour and pungency. Once fully dry, the pepper is stored in airtight containers or packets.

AIS also gives an idea of yield. A mature vine of seven to eight years gives 3 to 5 kilos of fresh pepper a year, which dries down to 1.5 to 2.5 kilos.

Pepper is a crop for the patient. The first berries take two to three years, and full yields come only when the vine is seven or eight years old. For anyone looking for quick cash it is not a main crop, but a long-term investment alongside other crops or an orchard.

Choosing the site takes balance. Pepper likes humidity and light shade, but in deep shade flea beetle multiplies and yields drop. Trimming the support trees now and then to let light in helps. Cuttings should come from healthy, high-yielding mother vines, because a diseased planting puts years of work at risk.

Pepper's economic strength lies in its long life. Unlike rice or vegetables it need not be replanted each season; a well-planted vine bears for many years. It needs no land of its own either. Mango and jackfruit trees, areca gardens and the trees around a homestead can all carry it. And because dried pepper keeps, a farmer can hold the crop for a while if prices are poor.

Demand in Bangladesh runs all year, and nearly all of it is now met by imports. More local production could replace part of those imports and give farmers a high-value cash crop. From homesteads in Sylhet and the hill districts to any humid, shaded yard in the country, a start can be made with one or two vines.

Behind the small black grain in the kitchen, then, lies a long-term farming opportunity. With the right soil, good cuttings, timely feeding and a close eye on pests and disease, pepper can become a source of income year after year. Farmers who are interested can seek advice first from the upazila agriculture office or BARI's spice research centre.

Photo: Green peppercorns on a black pepper vine, This Photo was taken by Timothy A. Gonsalves. Feel free to use my photos, but pl / Wikimedia Commons (CC BY-SA 4.0)