Cut Flower Production in Orchid

The Orchidaceae contain over 800 genera and over 25,000 known species of monocotyledonous herbaceous perennial plants. Prominent Genera Grown As Cut Flowers

1) Cattleya: A genus native to Central and South American tropics, cattleya has over 50 species and thousands of hybrids. Some species and their hybrids are photoperiodic responders and can be flowered twice in 1 year. The colors range from white through various shades of lavender, yellow, and red. Bicolors, white with purple lips, are available. Flower size ranges from 6 to 15 cm.

2) Cymbidium: Cymbidium is native to Asia and the Phillippines. The species and hybrids grown are the cool types requiring 10˚C night temperatures for flowering. Flowers (7.5-12.5 cm) are grown basically for spring trade, when their pastel shades are most fitting. However, flowers are available year-round since growers in Australia supply the northern markets during the Australian spring when plants in the United States are vegetative.

3) Phalaenopsis: These orchids, native to Asia, the Phillippines, and Indonesia, are very popular for use in wedding bouquets. White flowers, hybrids of Phalaenopsis amabilis, are available year-round as these plants can be maintained in flower continually. Pink and other colors are available in fall and spring.

4) Dendrobium: These natives of the Western Pacific basin are widely grown for their long lasting sprays of cut flowers. Thailand, Singapore, Hawaii are the largest producers of Dendrobium sprays. A typical Thailand spray is cut with seven flowers and seven buds. This large genus, with a wide variety of flower colors, sizes, and shapes, has great potential for cut flower production.

5) Vanda: These natives of Southeast Asia have long been popular plants. Probably the best known is Vanda Miss Joaquim, which has been used in Hawaiian leis for many years. It also has been widely used as a promotional flower. Vanda flower sprays are now being grown in Singapore, Thailand, and Hawaii. The latter are available throughout the year in a variety of sizes and colors.

6) Ascocenda: These hybrids of Vanda and Ascocentrum. Resemble miniature Vandas and have an excellent shelf life. Presently most of the cut flower production is in Thailand and all of the flowers are shipped to West Germany. Yields as high as 150 spikes m2

/ year have been reported.7) Arachnis and its Hybrids (Aranthera (Arachnis × Renanthera) and Aranda

(Arachnis × Vanda): These Southeastern Asia natives are widely grown as cut flowers in Singapore and Malaysia. They are grown in open fields with minimal care and produce up to 12 spikes per plant per year. One hectare is capable of producing between 660,000 and 799,000 spikes per year depending on the number of plants per hectare. A variety of colors is available.

8) Oncidium Golden Showers: A hybrid of Central and South American plants, this Oncidium is a very popular cut flower used in West Germany. Most of the production is in Singapore. Where the plants flower all year. The sprays of dainty bright yellow flowers are excellent for use in cut flower arrangements

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9) Paphiopedilum: The lady slipper orchids, natives of Southeast Asia, have long been popular cut flowers in Europe and the northern parts of the United States. Most of those cultivars grown are hybrids of species, such as Paphiopedilum insigne and require cool nights (10 ˚C) for best flowering, so production is limited to the more temperate climates. However, recent interest in the warm types, such as P. nivium and P. callosum , should lead to the introduction of more warm growing types , which could be produced commercially as far south as Florida.

Propagation Orchids are asexually propagated by several means. Seeds contain no endosperm and cannot germinate in the wild without the aid of a fungus. Knudson’s work led to the development of Knudson’s “C” Solution for orchid seed germination.

Orchid House and its Management

1) An orchid house is a structure that provides conditions suitable for healthy growth of orchids.

2) It should be located in an area not shaded by trees so that sufficient light is available and built in north-south direction lengthwise. A deciduous tree, in winter, on the west side may be advantageous, as it will provide shade in summer and will not obstruct sunlight in winter. Growing climbers like Ipomea, Passiflora, etc. on roof serves the same purpose. The floor may be slightly higher than ground level, as it will help in drainage during heavy rains.

3) Lath House : Inclined or flat roof orchid house supported by wooden posts embedded in a concrete base is particularly suitable for growing tropical orchids. The roof of such house is made of split bamboos or wooden slates 3-5 cm in width, placed in N-S direction leaving 2-4 cm gap in-between. In places with high rainfall, polythene films are used on such roof. The sides of the house may be kept open during monsoon or covered with wire mesh. Except pathways, the floor of the house should be covered with paved brick, porous gravel, pumice, cinder or similar absorbent material so that high humidity can be maintained inside the house. Long wooden benches should be provided to display the orchids in pots.

4) It is a good idea to have a water tank or reservoir or lily pools in the orchid house so that high humidity is maintained by evaporation. Pipeline inside the house is necessary for watering the plants. A built in spray system will be excellent.

5) Fibreglass House : Fiberglass roofing, providing uniform mild and diffused sunlight is used. This is generally provided with short walls over which glass-windows are fixed all round. Under subtropical conditions, the windows may remain closed to maintain the temperature. If necessary, heaters may also be provided. Advantages of this kind of orchid houses are – durability, cleaner environment, controlled watering, diffused sunlight and suitability in both tropical and subtropical zones.

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6) Controlled Glasshouse : The houses have either a heating system designed for tropical orchids to be cultivated in temperate conditions or air cool system designed for temperate orchids in tropical zone. Walls may be 1.06 m high and a roof pitching from the walls at approximately 45˚, the roof being constructed entirely of glass. Beams should be fitted under the roof for hanging epiphytic orchids which require more sunlight. Exhaust fans and ventilators are also provided to be used when required. During summer time it is necessary to partially shade the house by painting the top with lime or by using lath or strips of muslin or screen. The use of passive solar principles (wood construction, double glazing, insulated north and east wall) showed advantages in cold climates over traditional designs.

7) While watering in cool months in winter, hot water may be added to the tap water so that a temperature of 12.8 to 15.6 ˚ C is obtained. When planting medium is moist to touch, water should be withheld, but when it seems dry water should be given. Plants in basket require more water than those in pots. During cloudy winter months, watering may be done once or twice a week, but in summers, watering every day is necessary. A fine spray or light stream should be used for watering to avoid hitting the plants with much force.

8) During summer, sunny corners can be covered with split bamboos or moonj grass (Erianthus ravennae) nets to reduce inflow of hot air. Keeping ornamental foliage plants like ferns Anthurium etc. will add moisture to the house.

9) Suitable temperature has to be maintained in the house, the best range is 18.3 to 29.4 ˚ C. Variation between night and day temperatures should be about -13.3 to -12.2 ˚C.

10) Many tropical, subtropical, and temperate orchids including species of Aerides, Vanda, Dendrobium, Paphiopedilum, Cymbidium etc., grow and flower well in ordinary greenhouses in Darjeeling.

Composts, Potting Methods, And Containers

1) Epiphytic orchid can be grown in straight Osmunda fibre which consists of the intricate root system of two types of ferns of the genus Osmunda, found in moist places. It lasts longer and contains 2 to 3 % N2 which is released slowly as fibre decomposes. Polypodium fibre, a root system of another fern can instead also be used. Mixed compost of Osmunda with Sphagnum moss, is also being used. As a substitute for Osmunda and Polypodium, many orchidists use tree-fern fibers. These tree-fern fibers are very suitable for growing orchids in baskets or on rafts in small pieces about 1 foot (30 cm) long. They remain in good condition from 3-10 years in a greenhouse.

2) Many epiphytic orchids can be grown in clayey pots. Bigger pots have been found to encourage vegetative growth whereas plants grown in small pots produce better flowers.

3) Wooden baskets allowing sufficient aeration and drainage are most suitable containers for epiphytic orchids producing pendulous inflorescence. Wooden logs or blocks with the bark still on them are also suitable for growing many epiphytic

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orchids. About 10 cm in diameter and 25 cm long logs are good enough. Similarly coconut shells can be split into halves, bored, and used as containers.

4) Plastic pots are light in weight, easy to transport and do not accumulate algae or salts on their sides. Besides, they retain moisture longer than clay pots and therefore, the requirements of water is also less.

5) Glazed pots are not suitable, as they do not allow sufficient aeration of the roots and compost. The drainage hole at the bottom of the pot should be enlarged to assure adequate drainage, as good drainage is essential for successful growth of any orchid plant. About 1/3 rd to ½ of the pot should be filled with broken brick or gravel.

6) The Osmunda fiber should first be softened by soaking in water, and then cut into 1&1/2 to 3 inches (3.5-7.5 cm) square chunks.

7) Then the plant is carefully placed in the pot and covered by Osmunda fibre chunks. The rhizome or base of the plant should never be in touch with Osmunda fibre, as it may cause rotting of the plant.

8) If the plant has been growing on a 4-inch pot it should be repotted in a 6-inch pot. As the Osmunda fibers rot, after every two years, plants should be repotted. While repotting, old and deteriorated roots should be removed.

9) After potting, the compost should be dampened and foliage sprayed with fine spray of water. The pots should be kept in a warmer and shaded place till new roots sprout. As soon as new roots are established, the plants may be treated normally.

10) Newly potted orchid require less water than those well established. They should not be watered very frequently but the compost should be kept moist by fine spraying. As new roots emerge and growth starts, the plants need more frequent watering and it should be decreased again after flowering. Actively growing plants need more water than resting plants and orchid require less water in winter than in summer.

11) Cattleyas were reported to tolerate a wide range of water quality. Plants supplied with moderately hard water with a pH ranging from 5 to 9 made significantly better growth than plants given very soft water. Water with specific conductance values between 25 and 75×10-5mhos was considered suitable for orchid culture.

12) Hard water, however, should not be used in overhead sprinkler system because the leaves will be covered with a thin film of calcium crystals, resembling white salt on the leaves.

13) Water having a pH of not lower than 5.6 and not higher than 6.8 was found most suitable for the culture of Cymbidiums. The use of very cold water should be avoided as it may damage the leaves causing mesophyll collapse, resembling a virus infection.

14) Water having soluble salts less than 125 ppm was reported to be excellent for use, 125 to 500 ppm was good, 500 to be used with caution and salts above 800 ppm was suggested not be used.

Bark Preparation Bark preparations obtained from the shredded and / or chopped bark of a variety of conifers like Douglas fir, white fir and several types of pines and cedars are a new series

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of composts found to work better. The method adopted to prepare the compost is to remove the bark from the log and mechanically shred or cut the bark into chunks of varying sizes, which are steamed under pressure to remove the injurious resins. The smaller pieces are used for seedlings and bigger ones for adult plants. Small fibers and dust should be removed by sieving through wire net screens of fine mesh, as they may obstruct drainage. It is easier to put the plants in bark preparation than in Osmunda fibre. While transplanting established plants, care should be taken to remove old compost from the roots. The bark should be moistened several hours before its use, to facilitate potting. In wet regions, it is better to use it with an equal quantity of tree-fern fibre. The compost should be set properly by watering or placing the pots in water. The plants should be staked, if necessary, after placing them in the pots and thoroughly covered with the compost. More water is required for composts of bark preparation, as it provides for more drainage. As the bark preparations deteriorate more rapidly, it may be required to change them after every six months, which is a disadvantage. As these are deficient in nitrogen, regular application of a fertilizer with high nitrogen content will be required.

Cutting Flowers

1) Unlike many of our floricultural crops, orchid plants are kept for many years, so harvesting flowers are one cultural activity that is extremely important to growers.

2) Perhaps more viruses are spread when orchid flowers are cut than in any other way. Consequently, it is essential that all orchid flowers be harvested to avoid the spread of viruses. Disposable surgical blades can be used for harvesting. After harvesting the flowers from an individual plant it is necessary to change the knife blades before going on to the next plant. The blades can be sterilized and reused.

3) Cutting tools should be dipped in a solution of, trisodium phosphate or a saturated lime solution (pH 12), between the cutting of each plant.

4) In general, orchid flowers do not mature until 3 to 4 days old after thy open, so it is important to know how old blooms are before harvesting. Flower cut before they mature will not hold up and may wilt before they reach the wholesaler.

5) Harvesting should preferably be done in the evening. Dark coloured flowers may be as much as 5.5˚C warmer than white flowers during mid-afternoon.

6) Spray-type orchids present no problem. Each flower open 1&1/2 to 2 days apart. If three or more flowers are open on the spike, the lower flower is mature and can be harvested. Some growers allow the entire spike to open before they harvest, to ensure that the flowers are mature.

7) Cattleya flowers are a little more difficult to handle as it is very difficult, when there are large numbers of plants in flower, to determine when any one flower opened. Frequently more than one flower will open on the same spike in one day. One of the easiest ways to keep track is to have the grower go through the house each morning and insert a coloured golf tee, coloured plastic label or other such label in each pot where there is a flower opening. By using a different color each day the grower knows exactly when each flower opened.

8) When individual Cattleya and Cymbidium flowers for market are cut, the peduncle should be immediately inserted into a tube of water (orchid tubes with rubber or plastic covers). The tubes are generally filled from a pan of water that

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has been standing in the greenhouse overnight and has reached ambient temperature.

9) Spray-type orchids are cut and often shipped dry to the market. Some Dendrobium and Aranda growers immerse the entire spray of flowers in water for 15 minutes before packing and shipping. Some growers will wrap a little moist cotton around the base of stems before shipping and place 12 stems in a clear plastic bag.

Packaging

1) Cymbidium flowers in small tubes are packed 6, 8 or 12 in glassine-fronted boxes, ready to be made into corsages. Spikes of Cymbidium flowers are often packaged 100 flowers to a box.

2) Cattleya flowers are packaged in standard florist boxes. Tubes are taped to the bottom of the box and shredded wax paper is placed around flowers to protect sepals and petals in transit.

3) Hawaiian Dendrobium is packaged four dozen sprays per box. The standard box is 75×25×17.5 cm.

4) In Singapore, growers will pack up to 12 dozen stems of Arachnis Maggie Oei in almost the same size box. Nevertheless, when the box is opened in the market the sprays spring back to their uncompressed state.

Storage

Orchids, unlike many cut flowers, do not store for any length of time at - 1˚C. Flowers start turning brown in 3 days at this temperature and lose their salability very rapidly. Since most orchid flowers are long-lived on the plants, up to 3 or 4 weeks, growers will often leave them on the plants until they are needed. If they must be cut and stored they must be stored at 5-7˚C. At this temperature most orchids can be safely stored for a 10 to 14 day period. If orchids are not at their peak then storage time will be less. Plastic film storage is attractive and can be utilized. Foliar application of aluminum chloride at 500 ppm, ammonium molybdate at 100 ppm or boric acid at 1000 ppm lengthened the vase-life of Oncidium Goldiana. Hydroxyquinoline is also known to enhance bloom opening of the flowers and to increase the vase-life.ShippingThere are reports of some shipments of orchids arriving with flowers in a very bleached condition. Flowers such as Lavender Vanda Miss Joaquim appear to be a dirty white. This can occur when the pollinia have accidentally been removed from the flower and flowers have been shipped in a sealed plastic bag. If one pollinium has been removed, that flower begins to produce ethylene, which soon builds up in the container and bleaches the flowers. Punching a few holes in the bag, as for apple bags, will eliminate most of this problem.

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Consumer Care Immediately upon arrival, individual flowers are removed from the tubes. The lower 0.75 cm of the peduncle is cut off, and the flower is inserted into a fresh tube of water with preservative added. If the flower is made up in a corsage, the corsage is placed in the refrigerator at night and will last for many days, as it can be worn evening after evening. Spray-type of orchids should be handled in the same manner as gladiolus or chrysanthemums. The basal 2.5 cm of the stem is cut upon arrival, placed in warm water at 38˚C with a floral preservative, and hardened off at 5˚C. When used in an arrangement, a preservative is placed in the water to prolong shelf life. References:

1) ORCHIDS – S.K. Mukherjee2) Commercial Floriculture – Thomas J. Sheehan3) Commercial Flowers – T.K. Bose & L.P. Yadav

Assignment Prepared By: Date- 30.12.2005 Prit Ranjan Jha BSA03637

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