Vanilla Cultivation | Horticulture

Introduction

Vanilla is native of the Atlantic coast from Mexico to Brazil. It is grown on a plantation scale in Java, Mauritius, Madagascar, Tahiti, Seycheles, Zanzibar, Brazil and Jamaica and other islands of the West Indies. Malagassy Republic grows 70 to 80 per cent of the world's crop of Vanilla bean followed by Reunion. U.S.A. is the largest importer. This spice was introduced to India as early as 1835. Its commercial cultivation is now restricted to Wynad of Kerala and Nilgiris of Tamil Nadu. Recently, the demand for natural vanilla is on the higher side.

It is an orchid, belonging to the family Orchidaceae. There are two important species of vanilla viz. V.planifolia and V.pompana. The former species produces short thick pods whereas the latter one has the largest pods. V.planifotia has opposite, sessile leave of 10 to 23 cm long which are oblong in shape.

Climate and Soil

Vanilla requires a warm climate with frequent rains and prefers an annual rainfall of 150-300 cm. Partially uncleared jungle lands are ideal for establishing vanilla plantations. In such locations, it would be necessary to retain the natural shade provided by lofty trees which allows penetration of sunlight to the ground level and to leave the soil or the rich humus layer on the top undisturbed. However, vanilla is cultivated in varied types of soils from sandy loam to laterites.

Propagation

The crop is usually established by planting shoot cuttings. If possible cuttings with 18 to 24 internodes should be used as they come to flower earlier than shorter cuttings. But the length of the cuttings are to be adjusted depending on the availability of the planting material and the area to be planted. However, cuttings with less than five to sic inernodes and shorter than 60 cm in length should be avoided when planted directly in the main field. For raising rooted cutting in polybag even two nodes cutting can be used. It can also be propagated by using tissue culture methods. However, care should be taken to use plantlets not less than 30 cm in length.

The leaves of the fourth to fifth nodes from the tip are removed and the cutting is kept loosely rolled up in a cool, shaded place for tow to three weeks. When ready for insertion, the cutting must be handled very carefully. The lower three to four internodes are placed in a shallow trench 3-4 cm deep and about 10cm wide. The evacuated soil is used to loosely fill this trench. This operation is usually carried out at the beginning of the rainy season.

Land preparation

Preparing the soil for prospective pepper or vanilla plantations must take into account the need to supply each vine with a support or stake upon which it can climb. Later it will be seen that these supports are divided into two categories non-living and living. In the former, site preparation is unaffected because it is possible to put the non-living support, for example a wooden stake, in place at any time after the soil has been cultivated by general ploughing or hole preparation. Where living supports are used, these must be established before taking the cuttings from the pepper or vanilla plants. The supports most often used for pepper are either plants which are already in the plantation or trees from original forest growth, left in place during land clearance. In the latter case, the fact that the supports are already present makes it essential that the holes at the foot of each support are made by hand.

Planting

Vanilla, being a climbing vine requires support for growing. It flourishes well in partial shade of about 50 per cent sunlight and low branching trees with rough bark and small leaves are grown for this purpose. Some of the trees now being used include Glyrideidai, Erythrina, Jatropha carcas, Plumeria alba and Casuarna equisetifolia. If the support selected is a legume, it will be able to enrich the soil also. The growth of live standards is to be adjusted as to make them branch at a height of 120 to 150 cm, to facilitate training of the vines around the branching shoots. The standards are planted at a spacing of 2.5 to 3 metres between rows and two metres between rows and two metres within the row making a population of 1600 to 2000 trees per hectare. If limb cuttings are used for planting supports the ideal time is with the onset of rains after the summer, and it should be atleast six months before planting vanilla cuttings.

Vanilla is generally planted at a time when the weather is not too rainy or too dry. The months of August-September are ideal for vanilla cultivation. Cuttings for planting should be collected in advance, and after removing three or four basal leaves, dipped in one per cent Bordeaux mixture and kept in shade to loose moisture for about a week. Since establishment of cuttings is almost cent per cent, planting of single cutting per support is enough.

The defoliated part of the vine is laid on the loose soil surface and covered with a thin layer of about two to three cm soil. The basal tip of the cutting should be kept just above the soil to prevent rotting. The growing end is gently tied to the support for climbing by the aerial roots.

The cuttings are shaded with tall dry grass, palm fronds or with other suitable materials. In dry soil, a light sprinkling of water helps for early establishment of cuttings. It takes about four to eight weeks for the cuttings to strike roots and to show initial signs of growth. Vanilla can also be planted as an intercrop in coconut and arecanut plantations.

Mulching

This term refers to the act of spreading, on a cultivated plot, a fairly dense layer of a material which is usually, but not necessarily, of vegetable origin. This layer which should be as durable as possible, protects the soil from run-off and exposure to the sun, regulates rainfall infiltration, slows down evaporation, arrests or at least considerably restricts wed growth and is generally favourable to growth and yield since it also adds humus to the soil on decomposition. Mulching is used on many of the species studied, and is applied in various ways. mulching of vanilla is carried out as soon as possible, after planting. A mixture of grasses and leguminous species is recommended.

Training

If the vine is permitted to grow up on a tree, it will rarely blossom, so long as it is growing upward. Hence, vines are allowed to grow upto 1.50 m and then trained horizontally on the branch of supports and latercoiled round them. This induces more flower production in this portion of the vine

Flowering

The vines commence flowering in the second or third year depending on the length of cuttings used due to the peculiar structure of the flower, artificial pollination by hand is the rule for fruit setting. The procedure involved is simple and done easily by children and women. Using a pointed bamboo splinter or pin, another is pressed against the stigma with the help of thumb and thus smearing the pollen over it. Generally 85 to 100 per cent success is obtained by hand pollination. The ideal time for pollination is between 6 a. m to 1 a.m. Unfertilized flowers fall within two or three days. Normally 5 to 6 flowers per inflorescence and a total of not more than 10 to 12 inflorescences per vine are pollinated. The excess flower buds are nipped off to permit the development of other pods. Pods take six weeks to attain full size from fertilization but takes 4 to 10 months to reach full maturity depending upon the locations.

Maintenance of plantation

Once established, the vines have to be given constant attention. The plantation should be visited frequently to train the vines to grow at convenient level, to regulate the growth of the vines and the supports, to watch for disease and pests and to always keep leaf mulch around the vines. Any operation done in the plantation should not disturb the roots, which are mainly confined to the mulch and surface layer of soil. In vanilla plantations provided with living supports, adjusting the shading is linked with correct pruning of the supports, a task, which requires care and attention. In the first year, it is enough to prune the lateral branches so as to obtain a sufficiently high single trunk. Further growth in height is then prevented by topping the tree, which encourages the formation of a canopy but still provides light shade. Leucaena leucocephala is very well suited to this approach, as the pruning, which is left at the base of the tree, provide the soil with nitrogen-rich organic matter. With vanilla, the shading provided by the living support is often inadequate. It can be supplemented by planting a range of shade trees, for example, Albizzia lebbeck and Inga edulis.

When the support trees grow up, they are pruned early to induce branching. It is desirable to develop an umbrella shape for the trees to give better shade and protection to the growing vines. If the trees do not drop off leaves they are pruned before the commencement of heavy rains to allow in more sunlight. The pruned vegetation is chopped and applied as a mulch in the plantation. The way in which the vine is trained has an effect on flower production. If the vine is permitted to grown up on a tree it will rarely blossom so long as it is growing upward. For convenience of cultural operation the vines are allowed to grow up to a height of 1.2 to 1.5 metre and then trained horizontally on the branch of supports and later coiled round them. Alternatively two bamboo splits can be tied to two adjacent support trees and can be utilized for training the vines. Coiling of vines in this manner helps to accumulate carbohydrate and other flower forming materials, beyond the bend and to induce flower production in this portion of the vine.

Harvesting and curing

When immature, the bean is dark green in colour, but when ripe yellowing commences from its distal end. This is the optimum time for harvesting the bean. If left on the vine the bean turns yellow on the remaining portion and starts splitting, giving out a small quantity of oil reddish brown in colour, called the Balsam of Vanilla. Eventually they become dry, brittle and finally become scentless. Therefore, the artificial methods are employed to cure vanilla. Vanillin is developed as a result of the enzyme action on the glucosides contained in the beans during the process of curing. Basically any curing method involves the following four stages.

1. Killing the vegetative life of the beans to allow the onset of enzymatic reaction

2. Raising temperature to promote this action and to achieve rapid drying to prevent harmful fermentation.

3. Slower drying for the development of different fragrant substances.

4. Conditioning the product by storing for a few months.
i. Peruvian process: Curing is done by hot water. In this process the pods are dipped in boiling water. The ends are tied and hung in the open. They are allowed to dry for twenty days. Later they are coated with castor oil and afterwards tied up in bundles.

ii. Guiana process: The pods are collected and dried in sun till they shrivel. Later they are wiped and rubbed with olive oil. The ends are tied up to prevent splitting and then bundled.

iii. Mexican process: The harvested pods are kept under shade till they shrivel. Then they are subjected to sweating. This operation is carried out for two days depending on the weather conditions. In warm weather, the pods are spread over blankets and exposed to the sun. During midday the blanket is covered over and bundled and left in the open for the rest of the day. They are wrapped in blankets in the night to maintain continuous fermentation and sweating. The pods should be wrapped in blankets when they are hot to touch. This process is repeated for 7 to 12 days till they become dark brown in colour, soft and flexible. They are packed in tins and sealed. The Mexican process yields 4.15 to 4.40 per cent of vanillin content.

When the weather is cloudy, the pods are bundled in bales and wrapping with woolen cloth covered with banana leaves. They are subject to radiation of heat by maintaining the temperature of air-over at 50⁰C for 24 hours. Thereafter, they are dried to change the colour. Then they are spread in dry place and finally packed and sent to the market.

The most desirable beans will be 18 to25 cm long, dark brown. Highly aromatic, fleshy, free from mold, insects, and blemishes and somewhat oily in appearance. There are three grade viz. Grade-1, which includes whole beans of minimum 11 cm length, and grade-2 and 3 will have a minimum of 8 cm length. Vanillin extract is taken from the cured beans by hydroalcoholic extraction. The vanillin content of the properly cured beans will not be less than 2.5 percent.

Yield

The yield of vanilla varies depending upon the age of vines and the method of cultivation. Normally it starts yielding from the third year and the yield goes on increasing till the seventh or eighth year. Thereafter the yield slowly starts declining till the vines are replanted after another seven to ten years. In one acre you can plant about 1000 vanilla plants. Each plant is expected to yield about 500 grams of green beans per year. Under reasonable level of management, the yield range of a middle aged plantation will be about 500 kg of green beans per acre. If we calculate with minimum price of Rs. 150 for one kg, a year's income comes up to Rs. 75,000 per acre. Apart from the sale of green beans many vanilla farmers today are also making money by selling vanilla planting materials. Experts suggested that first time vanilla farmers should start by growing a few plants on a small plot of land. And then depending on the result they can expand the acreage.

Market for Vanilla

The main application of natural vanilla is for flavouring ice creams and soft drinks. It is estimated that nearly 300 tonnes of vanilla beans is used in USA every year in the preparation of cola type drinks. The major industrial purchasers of vanilla are pharma companies and soft drink companies like Coke and Pepsi. However the fact remains that market for natural vanilla essence is today largely only confined to the West. There is no market in India at the moment for vanilla essence. The domestic market in India is restricted to the green vanilla beans. In India processing companies buy green vanilla beans from the farmers, process it and then export the same to foreign buyers who then do the extraction of vanilla essence.

World production of vanilla beans is approximately 3000 tonnes per annum. Madagascar provides about 50 per cent of the world supply and the rest is from Indonesia. Comoro and Reunion. Production in Indonesia is nearly 500 tonnes. The present international demand from vanilla is about 19,000 tonnes.

India has just come into the market for production. Our production last year was a meagre 30 tonnes only. India is still a very insignificant player in vanilla. It will take some more time before we make our presence felt in the world markets. Presently Indian farmers are getting around Rs 150 per kg of green vanilla beans. The same green beans when they are processed fetch a price of around Rs. 1500 per kg. But processing technology in India for vanilla is still very primitive and many farmers are satisfied with just growing and supplying green beans. Considering the fact that cost of production is low, farmers are finding vanilla beans cultivation very attractive. In future more farmers will take up this crop and the production and export figures of vanilla will increase.

Vanilla imports are dominated by three countries- USA, France and Germany. Importers in Germany and France are suppliers to other markets especially in Europe. Europe imports generally high quality beans while USA accepts low quality beans also. There is an understanding between Bourbon vanilla producing countries viz. Madagascar, Comoro and Reunion, and importers of France and Germany in the marketing of vanilla beans.

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SPICES & CONDIMENTS : Vanilla Cultivation