Sunday, March 05, 2006

Why Must We Fertilize Orchids

Why Must We Fertilize Orchids

Written by [Philippine Orchid Review] Rudy and Soly Pagcatipunan
Sunday, 01 August 2004
Plants, orchids in particular, can live with just regular watering, but many do not grow vigorously or flower which we , as orchid lovers, desire so much.
Orchids through photosynthesis, can manufacture their own food for energy. Water (H2O) is absorbed through the roots and diverted to the leaves by capillary action. Underneath the leaves, are tiny opening called stomata, where carbon dioxide (CO2 ) gas can enter. With the aid of sunlight and the green coloring pigments called chlorophyll, carbon is fixed. H2O and CO2 will combine to produce sugar (C2H12O6-glucose ) and oxygen (O). Actually they do not produce simple sugar ( glucose ) but a more compound sugar, like hexose monophosphate, but for our purpose we just mention sugar. This sugar will be use by the orchid for its growth or maintenance of body parts.
From Air

From Roots


Photosynthetic Activity in Orchid Leaves
Water, whether from municipal or deep well, contain not only hydrogen (H) and oxygen (O). They contain several elements such as calcium, magnesium, chlorine and even nitrogen, phosphorus and potassium. For growth and flowering orchids need three (3) important elements and these are nitrogen, phosphorus and potassium (NPK). They maybe present in water but may not be available to the orchids. A good example is rainwater. Rain water it brings along some nitrogen from the atmosphere but the N cannot be utilized by the orchid in the form. It should be in the form of oxygen or nitrate or in much reduce form or ammonia (NH3). There are nitrogen fixing bacteria and the orchid mycorrhiza, fungi at the roots of orchids living in symbiotic relationship with orchid, both of which can convert nitrogen into a compound that orchids can use. Lightning can produce ammonia which can directly be used by the plants.
The earth atmosphere contain about 78% of Nitrogen. So then, when the stomata of the leaves open, it allow air to get in. Almost three-fourth (3/4%) of that air is nitrogen but he orchid can not utilize N in that form. An orchid is just contented to get CO2 from that air which h it need for photosynthesis. Even though CO2 is only about 0.03 percent of that air, they can get all the CO2 they need.
The other two important elements are phosphorus (P) and potassium (K) usually absorbed or utilized by the orchid in the form of potassium phosphate. There are other elements needed by the orchid but in the trace quantity, and these are magnesium, manganese, iron, copper, zinc and others.
In the wild, we can see orchids growing and flowering. The presence of orchid mycorrhiza or the symbiotic relationship with certain fungi like Rhizoctonia is so important to the orchid. While the fungi seek shelter on the orchid roots, it produce the necessary nutrients needed by the orchid plant. In its natural habitat, the seeds of orchids will not germinate unless infected with such fungi. And orchid pod contain minute powdery materials which are actually millions of seeds. When the matured pod breaks and the tiny seeds extruded, being so minute, they can easily be carried by the wind. When they latter will also produce the necessary nutrients for growth of the young embryo. Most germination, the bean embryo plant will utilize such nutrients for initial growth until it can produce its own by photosynthetic processes. Orchid seeds being so minute, unluckily do not have cotyledon.
So then, the orchids need to be fertilized in order to have the necessary nutrients it need for growth and flowering. There are two kinds of fertilizers, the organic and organic or chemical fertilizers.
Organic fertilizers are those derived from plants and animals. These could be guano (bat droppings), chicken manure, cow dung, animal (or human) urine or compost (decayed leaves, stem, roots, etc. of plants). Traditional orchid growers especially those in the rural areas, utilize fish washing to fertilize their orchids. Such is a good fertilizer but its users are inviting diseases, as decaying fish bloom, flesh and scales will attract insects like flies and ants. It is also common sight to see egg shells stuck in the orchid pots or media, with the idea that the left over egg-white in the shells will serve as fertilizers.
These organic fertilizers will be of importance for the growth of orchids as they are high in nitrogen. If used on matured plants, stem will be longer and leaves broader but may not induce to flower. Except for terrestrial orchids like Spathoglottis. It is difficult to apply organic fertilizers on epiphytic orchids like Vanda. As there are no known application processes so the amount of nutrient applied is unknown. Organic fertilizers when not properly prepared may also contain pathogen which may be detrimental to the health of the orchids.
The application of inorganic or chemical fertilizers is the easiest way to supply the orchid plants with necessary nutrients. If you are a chemist, you will have an advantage as you can prepare a fertilizer to supply the needed quantity of nutrients for growth or flowering. Fertilizers are prepared commercially, depending on the proportion of nitrogen, phosphorus and potassium (NPK) and areas available in plant nurseries or supermarkets. They are usually classified into two categories based on their effect on the plants, as grower or bloom booster. The growers preparation have higher concentration of N, than P and K, like 20-10-10. Bloom booster has the same or lesser quantity of N and P and K like 10-10-10 or 10-30-20. Usually 10-10-10 is called complete fertilizer as it has same proportion and all the NPK elements are present, but this is a misnomer above. Although these other elements are needed in trace amount, their presence is necessary to satisfy the needs of orchids.
Commercial fertilizers have instructions on their application. Usually, a measured quantity is dissolved in a known quantity of water and sprayed on the plants. Frequency of application is also mentioned. The orchid plants absorb the fertilized water readily by the roots, although the leaves and stem also do. The roots of orchids are covered with thick spongy layer called velamen which absorb water and its nut4rients and hold them for a longer time. There is also the slow release fertilizer in the form of small granules, which are applied on the pots or potting media or orchids. During watering, a small amount of fertilizer is released of dissolved in water. These fertilizers are usually applied by commercial growers to save manpower as each application of few granules will last for one or two weeks.
There are also cheap commercial fertilizers with proportionate amounts of NPK, which are used to grow rice, fruit threes and other agricultural plants. These are in the form of granules but these they are not recommended for orchids. These do not readily dissolve in fad water (except urea, which must be used with greater care), while directly applying the granules to the roots will damage the orchid plant.
Arditti, Joseph. 1987. Orchid Biology. Reviews and Perspectives, Vol. II. pp. 83-118, 173-212, 243-370, Vol. IV pp 105-192, 227-259; Cornell University Press, USA
Collier’s Encyclopedia. 1984. Vol. 17, pp 559-564; Vol 8, pp 765-772, Vol 23 pp 372-330
Davis, Reg S. and Steiner, Mona Lisa. 1982. Philippine Orchids, pp 1-35, Enrian Press, Bulacan, Philippines
PCARRD. 1994. The Philippines Recommends for Orchids. Los Baños. Laguna, Philippines
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Growing Phalaenopsis: Challenging but Rewarding

Growing Phalaenopsis: Challenging but Rewarding

Written by Chat Alejandro
Thursday, 04 August 2005
The butterfly orchids or Phalaenopsis as it is known scientifically is one of the most beautiful genera in the orchid family. Its shape and color combination make them look like row or cluster of butterflies on a slender arching stem.
In spite of this fascinating beauty not may people take an interest in collecting and culturing the butterfly orchid. This is due to the fact that the Phalaenopsis plant is so soft bodied and succulent that a slight wound would easily allow fungal or bacterial infection to the plant and eventually kill it. The Phalaenopsis is not a sturdy as its relatives like the Dendrobium, the semi-terete Vandas or the Epidendrum or the Spathoglottis. But there are a many number of orchid enthusiasts who are unfazed by the difficulties who accept the challenge with foresight and determination.
Cora Purification and her daughter Ana Ruth, do not only collect and grow Phalaenopsis, they also breed them. Cora’s late son, Eric who really fancied and this genus and seriously studied its culture, natural need and requirements and techniques in breeding started the interest in butterfly orchids.
Presently, the Purification orchid and ornamental laboratory and nurseries has thousand of plants form selected Phalaenopsis hybrid done by Eric some years back. Anna claims that bringing out the plants form laboratory flasks and transferring them form the sterile condition with artificial media to a natural environment needs extra care. Though the Phalaenopsis plant is vigorous in its germination and multiplication stages its succulent body is actually fragile and not as disease resistance as its other orchid relatives.
Anyone can succeed in raising butterfly orchids as long as this plants are provided the right care. Here are some pointers that Purificacion orchids and ornamentals Inc. wishes to share in growing and propagating Phalaenopsis beginning from flask.
Wash away the agar – agar or gelatin use as medium in the flask or bottle. Since the plant and its roots are soft and fragile, you must be extra gentle in handling them. Soak the plant in clean water to loosen and separate the gelatin from the roots. Then, in strainer with fine mesh, rinse the plant with fine running water to wash off the remaining chemicals.
If Phals are to be remove the community pot, gently loosen the media and disentangle the roots carefully avoiding much damage as possible. If roots are already clinging to the pots gently peel them off the pot with the paper knife
Remove dead and decayed roots and leaves, and then soak the plant in the fungicide solution (1 tbsp per gallon of water) for 10 min. Do the same to the plants taken out of the flasks. Use the protective cloves and avoid touching the chemicals and do not inhale the fume.
Biol the plant media for 30-45 min. and treat with the fungicide.
Sort the plants according to sizes. Bigger plants can be potted directly into small size 0” or 1 “ thumb pots with big drainage hole at the bottom. Smaller plant can be regrouped and planted in size 2” pots as a new community pot.

How to Produce more Flowers on Tour Dendrobium Anosmum or "Sanggumay?"

How to Produce more Flowers on Tour Dendrobium Anosmum or "Sanggumay?"

Written by [Philippine Orchid Review] Andres S. Golamco, Jr.
Tuesday, 01 February 2005
During the month of January and February the plants in nature experience the start of a Dry Period in the Tropics. Is also the time when the right time temperature is lower ( over 20F difference over the day time temperature ). These changes give signal to many plants species including the “ Sanggumay “ to produce buds and flowers.
However the drop of temperature and dry spell must remain constant and continuous in order to successfully initiate buds for the period of 4 to 6 weeks. Watering during this period must be strictly reduce or withheld for about 4 – 8 weeks, other wise fewer buds and flowers are produced.
Once the buds are formed to about 1-2 cm. long with most of the buds along the nodes developed, watering must be increased to daily ensure the proper development of the buds until the flowers have fully opened.
Larger flower are produced when watering is heavier when the flower buds are opening. Consequently, the petals and sepals are able to stretch to its fullest and widest dimension. With this technique applied, our “ Sanggumay “ Dendrobium can produce numerous chesters of large-sized flowers.

How to Flower Cattleya

How to Flower Cattleya

Written by [Philippine Orchid Review] Felix De Leon Flores
Sunday, 01 August 2004
In our 17 years of growing Cattleya, we often hear people complaining that hey cannot flower their Cattleya. That is why so many shy away from Cattleyas. But Cattleya is the easiest orchid to grow once you know how.
Upon investigation, it came out that the real culprit is the lack of proper light conditions. Some grow the Cattleyas in the porches of their houses. Others put them under the trees. Still others with greenhouses put too much shade. And mostly invariably they have 403 hours filtered light. Under these conditions, the Cattleya has lush green color, plenty of succulent and soft pseudobulbs and leaves but not flower. Naturally, this Cattleya will not flower although it looks very healthy.
A mature Cattleya to flower must have hard and firm growth with yellow green, hard and leathery leaves. And this can only be attained if you give your Cattleyas as much sunlight as possible, short of burning. Of course, you must also be using a well-balanced fertilizer for tropical conditions and a root hormone as a supplement.
Before citing orchid authorities to support the above statements, it might help us understand our Cattleya better if we know that Cattleya flowers only once a year in one lead. If your Cattleya has 5 leads (directions of pseudobulbs), then you will have 5 sets of flowers blooming at the same time or one after the other. It takes 8 to 9 months from the time bud begins to grow up to the time the flower opens. Also it takes 3 to 4 months from bud initiation to flower production. So how can a Cattleya flower twice a year, since there are only 12 months to a year? Of course, there are exceptions but these are very few. With the use of FFP hormone, we were able to flower a purple Cattleya twice in one lead in 13-14 months. So if you understand that your Cattleya will flower only once in one year per lead, you will not be so anxious and weary about your Cattleya culture. Most anxiety emanates from expecting too much.
Cattleyas have their own definite flowering seasons. Some are winter blooming, some autumn, others spring or summer. The result of crossbreeding also produces Cattleya that blooms in all seasons. The yellows and the reds are the hardest to flower. They need more light than the whites and purples. In fact, some concolor yellows will not flower, unless you withhold water to the point of shriveling. The reds need a cooler place but still needs an abundance of light.
Many factors affecting flowering of Cattleyas, namely, temperature, length of day, humidity, nutrients, and hormones. It is not only difficult to control temperature and day length but also very expensive. Let us control these factors with in our means, such as light, fertilizers, humidity, and hormones. Let us discuss the role of light in the flowering of Cattleya. The rest, while they are also important, are not so critical as light.
On pages 21 and 22 of the American Orchid Society “Handbook of Orchid Culture,” it is pointed out that “6 … Cattleya needs a good amount of light to grow and flower. A range of 2,000 foot-candles to 3,000 foot-candles is satisfactory even though Cattleya properly hardened can take up to 8,000 foot-candles and more.”
On page 59, Alex D. Hawkins (1961), in his book, Orchids: Their Botany and Culture, says … “in nature, orchids are found exposed to full sunlight … a few of these plants (meaning orchids) were found inexcessively shaded stagnant interiors of the jungles where light and free-movement of air is a premium,”
On page 69 of his book American Orchid Culture (1942), Edward A. White in discussing Cattleya culture says: “In their native habitat many species are found exposed to full sunlight. Light in adequate intensities is necessary not only in the production of good but to give firmness to the plant tissues so there are no soft succulent growths. Firmness of tissue seems to have direct relation to flower production, for when the growth is soft, fewer and smaller flowers are produced than when the plants are firm in texture. Color seems to be a good indication of light requirements. If the leaves are gray, green or dark green, it is an indication that he plants are receiving too little light, while shriveling of the tissues and clear, yellow color indicate too much light.”
On page 339, Carl L. Whitner (1953), in his book The Orchids: A Scientific Study, states and I quote “more and more it is realized that for good growth and flower production, and adequate abundance of light is necessary but also most invariably the plants with most light produce far more flowers and better growth. The nature plant (meaning orchids newly gathered from the jungles) have short, plumb, hard and leathery leaves and a distinctly yellow green color./ This is in contrast to the more succulent, dark green, narrow-leaved or tall plants that exemplify “soft” growing conditions and poor flower production. Herb Hagers’ (1954) ability to flower Cattleya two to a half years (normally it is 5-6 years) from flask is also the result of high light intensities (up to 4,000 food-candles which is about 80% of our full light of 5,000 foot-candles, 16 hours a day and a continued high levels of nutrients, humidity and water. Light is more often than not the limiting factor in growth and development. It is seldom that nutrients, water, carbon dioxide supply and temperature and other factors, though important, are in as critical a role.”
We quote from page 22, vol. 23, No. 2 Handbook on Orchids, published by the Brooklyn Botanic Gardens (1974): Failure to bloom healthy looking orchid plant is most often the result of too little light.
Page 81 on “How to Grow Cattleya” in the book published by the Oregon Orchid Society, Inc, Your First Orchids and How to Grow Them, says, and I quote: “To produce better growth and flowers a yellowish green shade is desirable. Too much shade produces dark green, soft growth which do not produce the best flowers. Medium light will result in lush green coloration and good flowers. A maximum of light yellows the leaves and produces the best flowering of the plants.”
I quote from Page 8of Orchid, a Country Side Book Publication (1979): “A Cattleya with lush, green leaves, and soft succulent growth is not receiving enough sunlight. A well grown plant receiving optimum light has leaves of yellow cast and a hard leathery texture. A heavy concentration of red or purple pigments (anthocyanin) in the pseudobulbs and leaves including as well as slight anthocyanin speckling in the flower sheath indicated good light cultures.”
All these authorities are agreed that maximum light short of burning is prerequisite for maximum flowering. At Antipolo, this will be 80% of full sunlight of 5,000 food-candles or 4,000 foot-candles in 8 hours or a total of 32,000 foot-candles-hours. The Cattleya has hard firm growth and hard and leathery leaves of yellow green color. Medium light (obtained in Antipolo by 50% lath house or 60% using 2 fish nets) giving 2,000 foot-candles to 3,000 foot-candles in 8 hours produces lush green leaves and good flowers. But Cattleya with dark green, soft succulent leaves will not flower.
The American Orchid Society Bulletin No. 10. Oct. 1977, on page 897, suggested that Cattleya needs a maximum of 25,000 foot-candles (16 hours usage per day). In our 17 years of growing Cattleya, medium light conditions of 2,000 foot-candles in 8 hours obtained by 40% through the use of lath produce lush green leaves and good flowers. At 50-60% of sunlight of 5,000 food-candles or 2,500 foot-candles to 3,000 foot-candles in 8 hours better growth and flowers are obtained. At a maximum light of 75% to 80% of 5,000 foot-candles or 3,850 foot-candles to 4,000 foot-candles in 8 hours produced hard firm growth with yellow green leaves and maximum flowering with a root hormone. The root system is tremendous. Also since the Cattleya are properly hardened they are not only resistant to top and root rot but also to fungus attack.

Growing Dendrobiums

Growing Dendrobiums
Written by [Philippine Orchid Review] Rolita V. Spowart
Sunday, 01 February 1998
Dendrobiums are one of the largest and the most diverse genera in the orchid family. This diversity in structure and habitat of the different species results in dissimilar cultural requirements between types. For this article, the discussion of the cultural requirements of Dendrobiums will be limited to the hybrids commonly grown in the Philippines. This category will include modern , intersectional hybrids mainly between the sections Phalaenanthe and not Spathulata. Occasionally, progenitors of these hybrids will include species from the section Latouria.

Dendrobiums are a delight to grow for hobbyists because of their affordable price, relative ease of culture and their diversity of form and color.

Potting and Mounting.

Proper potting or mounting is a vita aspect of Dendrobium growing as this will affect the development of the root system. A clean and robust root system should be single most important objective of a Dendrobium grower. With a healthy root system comes a dedrobium that can uptake water and nutrients readily and resist pest and diseases more easily.

The most commonly used potting media for commercially-grown Dendrobiums are charcoal,. Coconut husk and three fern fiber. While coco husk is an excellent medium, it disintegrates rapidly thereby requiring frequent repotting.

Charcoal and tree-fern fiber are more durable media for the non-commercial orchid grower. Dendrobiums mounted on kakawate twigs or driftwoods also perform exceptionally well under the conditions of the local backyard growers.

Light and Shade.

Dendrobiums grow very well under relatively high light. A shade of 30% (double fishnet) is adequate for growers who need artificial shade. Younger Dendrobiums will require more shade (50%). For growers who cannot stand to have netting installed in their gardens, Dendrobiums should be positioned in an are that gets full sun from dawn till about 11:00 o’clock am and shade or filtered light thereafter.

Heavier shade will result in Dendrobiums with lusher, dark green foliage on taller plants while higher light intensity will result in more blooms. It is wise to provide more shade to Dendrobiums at heir younger stage while they are foliage. As soon as they are ready to bloom, provide higher light intensity to ensure early flowering.


The frequency of watering is dictated by growing conditions. Conditions of higher light intensity and stronger air current require heavier, more frequent watering. The growing media is also a factor to consider in adequate watering. Coco husk retains moisture longer while charcoal dries out quicker. Dendrobiums mounted on driftwoods will require daily watering as the roots are continually air-dried without the benefit of a water-retaining medium.

Many experts advise Dendrobiums to be watered enough so that the pseudobulbs do not shrivel. Any more than this will promote root and leaf diseases. Providing less water to the point of shriveling will result in leaf loss.

Dendrobiums favor their roots to be constantly moist while their foliage to be dry. Dendrobiums will adjust slowly to the level of watering that they are given. Give them too little and they will develop more roots and thinner, smaller leaves. However, it is important to note that drastic changes in moisture level will result in leaf loss and bud drop. Changes brought about by climate conditions should be aided gradually.


Dendrobiums are fast growing orchids that require heavy feeding. Commercial growers are known to fertilize their Dendrobiums at one and a half times the recommended rate at 3 times the recommended frequency. This will work so long as the other requirements and conditions are ideal.

Hobbyists will varying growing conditions will be on the safe side if they apply a balanced fertilizer at the manufacturer’s recommended rate. A higher nitrogen fertilizer will be required for younger plants.

A one to two-time-a-week washing or heavy watering in between fertilizer application will ensure that salt build-up in the plant and the growing media is prevented.

Important Considerations

While Dendrobiums are fast-growing plants if they are grown under ideal conditions, they are also one of the most temperamental of orchids. As a great majority of the species progenitor are deciduous in nature, these modern hybrids respond similarly to sudden changes in growing conditions. Drastic changes in temperature, moisture or light level and the slightest injury to its roots almost always result in bud or leaf drop.

Commercially Important Cultivar Groups

UH Varieties

The cut-flower varieties of the University of Hawaii is a commercially important group of cultivars as they are ideally suited for cut-flower production. While these groups does not exhibit the more spectacular form and color of other newer hybrids, their performance in floriferousness and vigor is extraordinary.

Purple Phalaenopsis Types

D. Udomsri is the typical example of this group. The large , round flowers of deep velvet dark purple colors remain popular only in the cut-flower trade but also for the potted-plant market. Larger, darker flowers of thicker substance on more vigorous plants have been the prevalent improvement in he newer hybrids of this type.

Yellows and Greens

Mainly descended from the species D. schulleri, these modern Dendrobiums have excelled in their color and from in the past decade. D. Tongchai Gold from Thailand and D. Palolo Sunshine from Hawaii are some yellow hybrids of significance. D. Bangkok Green, D. Burana Fancy and D. Burana Jade of Bangkok are commercially significant greens.


The bluer color is a sought-after shade in the Dendrobium pot-plant market. Important progenitors of the blue Dendrobiums are D. taurinum and the blue form of D. gouldii. A true sky-blue colored Dendrobium remains to be many a breeder’s dream.

Horn and Semi-Horn Types

Malaysian breeders have long created hybrids of these types from D. taurinum, D. lasianthera, D. helix, and D. strebloceras. Hawaiian breeders of old have made use of D. gouldii, D. stratiotes and D. cannaliculatum for their horn type breeding.

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Strategies in Clonal Mass Propagation of Orchids

Strategies in Clonal Mass Propagation of Orchids

Written by [Philippine Orchid Review] Norberto R. Bautista
Friday, 01 February 2002
Orchids are valued for their exotically beautiful flowers. They are economically important crops for they are used in cut flower business, while some are valued as a potted plant collected by numerous orchid collectors  hobbyist around the world. With a large demand, orchids can be reproduced by the millions and each seedling is an exact duplicate of its parent.
These plants are propagated either by the conventional and the non-conventional means. Conventional means of clonal propagation means reproducing orchids asexually through divisions of pseudobulbs, top-cutting in monopodial orchids, or induction of keikes (anak) through the use of plant growth regulators or subject to stress. This method is used by the hobbyist in reproducing their collections in their gardens. Unfortunately, this method is slow (produces about 2-3 plants a year) and the plant is in the risk of being infected with the viruses.
Non-conventional means of propagation involves reproduction through plant tissue culture. Unfortunately, this method needs a sterile laboratory wherein all manipulations can be done and the plant tissue to be use is grown in an artificial culture medium under artificial lightning and temperature. It is capital, technological and labor intensive, but if done right, produces millions identical progenies from a single mother in just 1 year!
Although plant tissue culture is the fastest way of cloning orchids, sexual propagation (seed culture) which could be done either by dry seed method or through the green capsule method is still the second most fastest and surest means of propagating orchids. However, this method produces a lot of variant offsprings and are not all true to type.
The development of the technique of plant tissue culture of orchids and its practical usefulness needs to be created to Morel in 1952. Also, the development of various protocols and studies on the micropropagation of orchids in the Philippines needs to be given recognition.
Contributory to these are the works of Dr. Valmayor, Prof. Sajise, Prof. Arquiza, and Dr. T. Amore. Some foreign scientist which are also very important in the development of orchid micropropagation are those of Murashige, Skoog, Arditti, Sagawa, Rotor, Vajrabhaya, Kunisaki, Teo and others.
Plant tissue culture is a broad term which means the growing or cultivation of plantlets or plant parts in an artificial culture medium under aseptic conditions, The orchid industry was one of the most benefited with this technique because is the only means of mass propagating orchids. With the success in orchids, the technique was adopted to other ornamental plants. It is a generic name which includes the following techniques:
Embryo culture/embryo rescue – culture of isolated mature or immature embryos (seeds). It is a sexual means of propagation, but nevertheless, orchids produces thousands seeds (20,000 – almost a millions in some species). However, there is a great variation within offsprings. This is a very ideal for hybridization works. Also, based from Kamemoto et al (1999) there is no case yet that viruses from an infected mother plant is transferred to the seeds if dry seed method is used. Thus, It is also a means of producing virus free orchids from virus infected ones.
Shoot tip culture – culture of an apical meristem with some leaf primordial attached, in an effort to produce plantlets. These technique in orchids usually puts the mother plant in danger of death a sacrificing the mother plants. However, other techniques can be used like the use of flower buds.
Meristem culture – culture of the apical meristematic dome. It is popularly called “mericloning’’. The technique is similar to shoot tip culture, however, the term is strictly refers to isolating the apical dome. The explant is much smaller compared to that of the shoot tip. This is technique is done to primarily eliminate viral diseases in orchids.
Tissue (or callus) culture – culture of tissue arising from explants of plant organs like meristems, leaves, roots etc. and induced to form a callus (undifferentiated mass of dividing cells), which is prelude to production of protocom like bodies (PLB) and could later be induced to regenerated into whole plants. Most of the procedure in plant tissue culture pass through this stage  formation of callus.
Organ culture – culture is isolated plant organs like leaf, very young & undifferentiated flower buds, nodal segments of flower buds, roots and buds from pseudobulb or stem and permitted to form callus, undergo embryogenesis and regenerate into whole plants.
Anther culture – culture of anther (pollinia) or immature pollen grains in an effort to obtain a haploid cell or callus line. These haploid cells can be induced to become diploid by chemicals like colchicine (or other substances, while other automatically become diploid). These is useful in obtaining orchids with pure recessive lines.
Cell suspension culture – culture of isolated cells or very small aggregates of cells remaining dispersed in liquid medium. It is used prior to protoplast culture, or for production of protocom like bodies.
Protoplast culture – culture of naked cells (plants cells devoid of their cell walls using a cellulose digesting enzyme). Protoplast can be use in protoplast fusion (or genetic engineering), wherein two separate genomes can be combined into one cell, and the cell regenerated into a whole plant. A transgenic or genetically modified orchid (GMO) can be produced.
The steps in orchid micropropagation involves (a) selection of mother plants (b) sterilization of explant (the tissue you are going to use in tissue culture); (c) initiate culture; (d) proliferation, subculture and division of the plant tissue until desired number of plantlets are obtained; (e) differentiation and regeneration of tissue who plants and rooting; (f) acclimatization in the greenhouse; and (g) outplanting (compotting).
Culture media used for orchid micropropagation are Murashige & Skoog’s Media (MS), White’s Media, Knudson C Media, Vacin & Went Media, R Media, Gamborg B5 Media, Nitsch & Nitsch Media and a lot more. These media are usually supplemented with coconut water, sugar, and plant growth regulators (benzyl adenine, naphthaleneacetic acid, indolebutyric acid or kinetin).
There are a lot of advantages of micropropagation over the conventional means. Primarily it produces numerous propagules in relatively short period of time. It also uses relatively smaller space than conventional propagation methods. Propagation can be done all year round independent of seasonal changes. The technique also produces large number of disease-free planting materials, free from viruses, fungus, & bacteria. Thus they are not subject to quarantine during transport. However, virus indexing is still a necessity to absolutely certify that the plantlets are virus free. The technique can be use for conservation works and the storage of the plants are free from environmental risks. Since they are inside the lab, no labor and materials for watering, weeding and spraying of pesticides are needed and no care and attention is needed between subculture. Lastly, due to small size of orchid seedlings, they are less bulky to transport.
Plant tissue culture also has its drawback compared to the conventional means of propagation. First of all, it requires staff with high technical skill for successful operation. It also requires specialized and expensive production facilities, laboratory and greenhouse. It also need fairly specific methods or protocols to obtain optimum results from each species. Labor is also intensive (due to subculture), resulting in high cost of propagules. Plantlets obtained are initially small, and are not autotrophic and plantlets are susceptible to water loss. Plantlets need to undergo a transition period of hardening in the greenhouse. And lastly, there are chances that some laboratories could produce genetically aberrant plants due to extensive use of plants growth regulators. In order to prevent this from happening, plant with unstable genomes needs to be subcultured only up to the 7th subculture; after which, “ old cultures” are replaced with fresh new initial cultures.
Identify reputable sources of mother plants – Mother plants are very important in micropropagation, because it is from them where your initial plant tissues will come from. Motherplants which are disease free, properly indexed, and with desirable characteristics (with award winning qualities) is a necessity. The location where the plants are grown needs to be clean (no sources of contamination e.g. mushroom growing area, soil bacteria, or far from diseased plants, pollution free). It is also ideal that the plants to be used as motherplants be grown inside a greenhouse protected from the elements. Also orchid collectors are good sources of mother plants, especially if they have vast collections of different species and hybrids.
Identify & Designate a Service Laboratory - A laboratory equipped with technical capability and sufficient physical facilities which will do the job of micropropagating your orchids needs to be identified. The lab needs preparation room, a transfer room and a culture room. The laboratory operator needs to be capable enough to produce the number of seedlings you need. At least they need also a greenhouse large enough that can acclimatize the plants (compotted) before they are returned back to the client.
Designate a greenhouse or nursery specialist – In case the laboratory does not have a greenhouse, someone with expertise in out-planting and compotting orchid seedlings from flask is an additional requirement to successfully grow orchid seedlings. People in the orchid industry need to specialize into laboratory technicians, nursery men, orchid growers and sellers to simplify the process of orchid growing.
Availability of orchid growing technologies & information –There is a need for technologies in all aspect of orchid culture be readily available to all, especially to the orchid industry. Nowadays the advances in information technology (computers) are beneficial. This can be done by creating linkage or networks with the academe (local and international), government & private agencies, the orchid industry and the orchid societies or organizations. Another option is to have continuous training programs for new and emerging tissue culturists, orchidists, orchidologists, and taxonomists, so that knowledge is passed on to your younger generation
Orchid marketing plan – Market studies needs to be done through consultative meetings between the participants in the orchid industry to identify different problems, either technical or marketing. With this, new markets (locally or overseas) can be identified and targeted. Also, orchid trends and novelties can be identified. Thus, orchids which are mass-produced have sure markets.
Orchid Breeding Plan – There is a need to have an orchid breeding plan to continuously create new orchid hybrids for the cutflower & potted plants industry. This can be done by motivating local orchid breeders to pursue breeding works and selection of orchids with outstanding characteristics. These new hybrids will be the one which will be mass produced.
There is already a vast sea of information on orchid micropropagation. It is just a matter of identifying this information, teach it to interested persons, train them further, & provide sufficient finding to accomplish specific orchid propagating projects. It is an irony that the Philippines is a good teacher in terms of agriculture, but somehow we are being left behind by our Asia neighbors in capability of plant mass-propagation.
ROBERT. 1993. Micropropagation
Of Orchids. New York
John Wiley & Sons, Inc.
ARQUIZA et al. 1999 Orchid
Micropropagation (unpublished),
Philippines University of the
Philippines at Los Banos,
College, Laguna
1999, Breeding Dendrobium
Orchids in Hawaii. Hawaii
University of Hawail Press.
KANG, LEE CHEW. 1983. Orchids:
Their Cultivation &
Hybridization. Rev. ed. Malaysia
Eastern Universities Press SDN.
PCARRD. 1998. The Philippines
Recommends for Orchids
STEWART, JOYCE. Ed. 1992. Orchids
At Kew. Singapore. HMSO
Publications Centre
Orchid Tissue Culture Laboratory
Research & Development Center
Rizal technological University
Boni Avenue, Mandaluyong City
He can be contacted at ( 632)533-6041 loc. 124

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Philippine Species Highlight: Vanda luzonica Loher ex Rolfe 1915

Philippine Species Highlight: Vanda luzonica Loher ex Rolfe 1915

Written by [Philippine Orchid Review] Carla Cubero Quiano
Friday, 01 February 2002
March 17 1991 was a very unusual day for people living here in Central Luzon. On the afternoon of the day, a cloud of white ash however over the whole metropolis and blanketed everything from rooftops from trees, cars and roads. People who dared venture out during those days suffered itching and stinging sensations in their eyes, skin and scalps not to mention aggravated pulmonary problem.
This was the day that Mt. Pinatubo erupted. In its wake it cause a lot of damage to properties and left so many people, specially the Aetas of Zambales, homeless. For an orchid enthusiasts like me it means the destruction of an orchid sanctuary particularly the natural habitat of the Vanda luzonica.
Vanda luzonica, like the plant featured on our front cover has always been known to come from the Mountain of Zambales. Although it was reportedly been found in Bulacan, Tarlac and Rizal. I have yet to meet of an orchid collector who has acquired one of those places. If this in indeed true then we can still console ourselves with the though that there are still other places in the Philippines where we can find Vanda luzonica growing in the wild.
Vanda luzonica is epiphytic and can grow quite large – reaching about one meter in height. Leaves are 2 ranked, dark green, sometimes twisted, about 25-40 centimeters long and 2-3 centimeters wide. The inflorescence is racemose, axillary’s and about 12 –16 inches long. The followers are loosely space along the spike and are waxy. The sepals and petals are white with purple plash pink spots and marking near the tips. The petals are often twisted. The lips are magenta purple with 6 dark purple lines and a white spur. It flowers during the month of January, April, November and December.
At the POS Annual Orchid and Garden Show last Feb. 2001, a Vanda luzonica romped-off with a major award. ( see photo Front Cover ) Sheila Johnson, who exhibited this particular specimen, shares with this writer some tips and insights on her plant.
According to Sheila, her mom who loves collecting Philippine orchid species, purchase this particular plant back in 1977 from one of her customers. It was never given any special treatment since it grew along side the imported orchid hybrids that they sell in their nursery. She said that all their orchids whether “ native “ or “ imported “ received the same attention.
They follow a weekly regimen of feeding with a balance fertilizer followed by a bloom booster and supplement it with rooting hormones. Because their nursery is in hot and sunny Pampanga, they usually put one layer of the net during the summer and water as much as three times a day depending on how hot or windy it becomes.
During the rainy season they applied fungicide on a weekly basis as a prevented measures.
Sheila also observed that some of their newly acquired Philippine orchid species do not flower for a couple of seasons. She advises that you have to be patient and continue to care for them, Though it may take a while for Philippine orchid species to acclimatize and get use to their new environment, they will one day just surprise you with beautiful blooms.
(suitable for Vanda luzonica )
Light: Strap-leafed Vandas need about 50% shade and 50% light.
Water: They need relatively humid environments to thrive and grow well. Since strap-leafed Vandas don’t have bulbs to store water for long periods of time and since most of them are planted on basket with all of their roots exposed, they need to be misted several times daily depending on how hot or windy it is. This is to prevent that plant from drying out completely
Fertilizer: Alternately apply a balance fertilizer and a bloom buster on a weekly basis. For more frequent application it is best to dilute a recommend dosage by half or ever lesser. Remember to water before applying fertilizer so as not to bum the tender and sensitive roots.
Flowering: One or more flower spikes are produce at a time from leaf axils on the upper part of the stem. Once the spikes appear they grow rapidly. Frequent watering should be maintained to prevent the tip of the growing spike from shriveling prematurely. A spike will grow towards the light so it is best to position the plant so that the light leads the spike sideways or out of the channel of the leaf.
Vegetative Propagation: Vegetative propagation in strap-leafed Vanda’s though top cuttings may be quiet slow since most of them do not grow fast nor produce roots on the upper part of the stem. When doing a top cut from a strap-leafed Vanda you should make sure that the portion to be cut has at least 2 to 3 active roots to support the new growth. On the other hand, the lower remaining part should at least have 3 to 4 sets of leaves in order to produce Kiekis. A leafless stump will not produce offshoots. Older plants will quiet often produces side shoots from the base of the stem, which can be separated when they have their own roots.
Problems: Vandas are quiet robust and will stand regular spraying of fungicides and insecticides. They are quiet susceptible to root and crown rot and are often infected by fungus ( Guinardia ) that leads to unsightly black steaks along the leaves. The roots are rather slow growing, and if attacked by cockroaches or snails, root growth can be slow.

The Tiger Orchids

The Tiger Orchids
Written by [Philippine Orchid Review] Kelvin Neil B. Manubay
Sunday, 01 February 1998
This year 1998 ushers in the lunar year of the Tiger. And, what better way for orchid lovers to welcome the year but with the showy blooms of the ‘Tiger’ orchids.

The flowering of orchid species are always initiated by the climatic changes in our environment. The entrance of the first new moon, which signals the start of the lunar year brings with it the transition from short days and cool nights of December to the warm nights and long days of the late January. This occurrence brings with it the flowers for the first quarter of the year. Coincidentally, ‘Tiger’ orchid blooms are the ones that dominate this first part of the year.

Without the taxonomic guide, traditional folk started naming orchids based on the apparent characteristics of the plant. A case in point is Phalaenopsis schilleriana. It is perhaps the most popular among the orchids commonly known as the ‘Tiger’.

Phalaenopsis schilleriana is found in the low laying areas of the south from Laguna, Quezon, Rizal, Marinduque and Bicol up to the eastern side of the Visayas. Its plant is characterized by distinct gray and white barring that marks its broad green leaves. This characteristic has been likened to the barring found on a tiger’s coat, thus the common name ‘Tiger’. This particular species produces masses of pink flowers on long branching sprays that last for about two weeks. Although it is quite difficult to make them flower in Manila, many still keep them for their very attractive foliage.

Another such species is the Phalaenopsis stuartiana. Its plant resembles that of the Phalaenopsis schilleriana but the flowers are white with distinct red purple spotting along its center. This plant which his found in the lower laying areas of Agusan, Bukidnon, Misamis Oriental, and Surigao readily flowers even in Manila during this time of the year.

On the other hand, Trichoglottis fasiata has also been referred to as the ‘Tiger’ orchid because of the cinnamon-brown bars that distinctly mark its flowers. This species can be found growing on trees in Agusan, Rizal, Sorsogon, and Leyte at altitudes ranging from 60 to 800 meters. It is a very adaptable plant and can easily be grown and flowered in Manila. Its blooming season starts at December and stretches out up to March.

One orchid genus that lays claim to the most number of species referred to as ‘Tiger’ is the genus Grammatophyllum. Although their flowers are generally marked with elongated spots, which is likened to that of a leopard, the consistent patterns they create are more like the patterns on a tiger’s coat. The Grammatophyllum species that are commonly called ‘Tiger” are Grammatophyllum scriptum and its variant tigrinum, Grammatophyllum measuresianum, Grammatophyllum speciosum and the grandest of them all the Grammatophyllum wallisii. Flowers of these genus are normally numerous and are borne on flower spikes that reach u to 5 feet long, with the exception of Grammatophyllum wallisii whose flower spike could grow up to three meters long. Grammatophylums are generally easy to grow and flower.

These are just a few of the orchid species that flower during this time of the year. What makes them special is their being likened to that of a tiger. The Chinese believe that hanging images of the tiger during the Tiger year can bring strength, wisdom, courage and power. Why don’t we add “beauty” to these traits by growing ‘Tiger’ orchids as well?

Flowering of Orchids

Flowering of Orchids

Written by [Philippine Orchid Review] GOH CHONG JIN
Sunday, 01 June 1986
THE ORCHID FAMILY is one of the largest families in the plant kingdom. It consists of about 600-800 genera with a total of 20,000 to 30,000 species (Garay, 1960; Schultres and Pease, 1963). Orchids are widely distributed in all parts of the world except the extreme cold regions where no flowering platns can survive. They are found most abundantly in the dense tropical forests, but can also be found on open grasslands, hto and dry deserts, cold and damp rocks subject to constant sea spray (Arditti, 1979), and even subterranean, underground, as in Rhizanthella gardneri, a monotypic genus from Western Australia (Nicholls, 1969).
All of us who are familiar with orchids are aware that many of them have definite flowering seasons. This is more pronounced in species and hybrids from temperate rather than tropical regions. Amongst the topical orchids, many have peak flowering periods even if they flower throughout the year. Many keen orchid observers have reported the flowering dates and periodicity of orchids under natural habitats. For example, Curtis (1954) recorded the annual fluctuation in rate of flower production by native cypripediums; Dunsterville and Dunsterville (1967) reported on the flowering season of Venezuelan orchids and Quisumbing (1968) on the Philippines orchids. The most extensive observations were carried out in West Africa by Sanford (1971). All these observations showed presence of flowering seasons and point to the fact that flowering in orchids is regulated by some environmental factors.
Two important factors which control flowering are light and temperature. The effect of light is not obvious in the phenomenon known as photoperiodism, but light intensity and light quality are not without effects. Temperature effects are expressed in vernalisation and thermoperiodism.
Daylength varies with the season in most part of the world. Days become longer in the spring following the shortest day (December 21st in the Northern Hemisphere) in the winter. They reach a maximum during the summer (June 21th in the north) and then decrease again in the autumn. The variations in daylength are very small near the equator (about 10 minutes in Singapore – Holttum, 1953), and increase towards the poles. This means that orchids growing in different regions are subject to different daylengths or photoperiods which vary with the seasons.
There are basically three types of responses to photo9periods: long day plants. Long day plants are those which flower (or flower more profusely) when the daylength exceeds a certain minimum (called critical daylength). Short day plants flower when the daylength is shorter than a certain maximum. The day neutral plants flower irrespective of the daylength, that is, they are indifferent to day-length, but may be controlled by some other factors.
It has to be emphasized that long day or short day does not mean longer or shorter than 12 hours of light respectively. A long day plant may flower under 10 hour day or a short day plant may flower in 13 hour days. However, in the case of the 10-hour (critical period) long day plant, as the day length increases, the flowering process is greatly stimulated and accelerated, and it will not flower at all if the daylength is shorter than 10 hours. The reverse is true for the short day plants. In nature, long day plants flower on the increasing daylength of spring and summer. Short day plants flower with decreasing day length in the autumn.
Although photoperiodic effects on flowering was well established it he 1920’s, studies in orchids apparently did not commence until the 50’s. Gavino Rotor Jr. was one of the early researchers in of two weeks (Goh, 1977; 1979; Goh and Yang, 1978;) on Cymbidium, Dendrobium, Paphiopedilum and Phalaenopsis when he was a research assistant at Cornell University, Ithaca (Rotor, 1952). Until today, only a few studies have been reported and the number of species or hybrids examined is extremely small. Some of the orchids with known photoperiodic responses are listed in Table 1. It may be noted that some of those listed are deductions from flowering dates under natural environments (Sanford, 1971). In some studies (e.g. Bhattacharjee, 1979), plants were subjected to continuous long day or short day treatments throughout the whole year. These observations would require further confirmation. In many other plant with photoperiodic requirements, only a few cycles are needed to evoke the flowering process: our studies with Aranda as well as Dendrobium hybrids showed that floral bud initiation can be effected within a period of 2 weeks (Goh 1977; 1979; Goh and Yang, 1978). Therefore, orchids which appeared to require long periods of day-length treatments for bud initiation could be regulated by some other (or additional) factors.
As mentioned earlier, most of the orchids which respond to short-day or long-day photoperiods are temperate in origin. The claim that “… tropical (orchid) plants are more sensitive to small differences in daylength than are temperate-zone plants” (Sanford, 1974) needs further study.
In the greenhouse, photoperiods can be extended by the provision of artificial illumination (incandescent or fluorescent lamps) at the end fo the day, or by breaking long nights into two short night periods with an half hour artificial illumination in the middle. Conversely, days can be shortened by covering the plants with black cloth during part of the day. Practical growers can use the photoperiodic requirements of orchids to regulate blooming time, by either inducing flower production with appropriate photoperiods or delayi8ng it with unfavorable daylengths. For example, Cattleya gaskelliana when grown at 65 oC (18 oC) is a long day plant with a critical daylength of 16 hours. It also requires three to four months from bud initiation to flowering. So, when grown at 65 oF (18 oC) these plants should be given 16-hours days (or long nights with a half hour light break in the middle), three-four months before the flowers are needed. On the other hand, Cattleya labiata (and its hybrids) flowers on short days (critical daylength 16-1/2 hours.) Therefore, to obtain flowers for Christmas, the plants should be kept at 65 oF (18 oC) under long days (or given a half hour light break at the middle of long nights) until September 25th (or round-about) and then kept under daylength of 16 hours or less.
Table1. Examples of orchids with known photoperiodic responsesLong Day Plants Short Day Plants Day Neutral Plants Aerangis biloba* Brassavola nodusa Arachnis Maggie Omei Cattleya gaskelliana Cattleya amabilis Aranda Deborah Cyrtorchis hamata* Cattleya labiata Aranda Wendy ScottDiaphananthe curvata* Cattleya mossiae Cattleya Enid Eulophia guineensis* Cattleya trianae Dendrobium Jaquelyn ThomasLaelia purpurata Cattleya Bow Bells Dendrobium Lady Fay Miltonia anceps Cattleya Jean Barrow Paphiopedilum insigne Miltonia spectabilis Dendrobium phalaenopsis PhalaenopsisOdontoglossum bictonense Phalaenopsis amabilis Vanda Miss JoaquimPolystachya modesta* Renanthera imschootiana Rhyncohostylis gigantea
* Probably, deduction from flowering dates in nature (Sanford, 1971). For details, see Goh, Strauss and Arditti (1982).
Light Intensity
Many tropical orchids are day neutral plants,. For example, Vanda Miss Joaquim. However, they also exhibit peak flowering seasons. In Hawaii, the seasonal flowering of Vanda Miss Joaquim was shown to be correlated with sunlight availability. Reduction in sunlight by the use of saran-cloth cover resulted in progressively later, commencement of flowering and lower yields (Murashige, Kamemoto and Sheehan, 1967). Similarly, when the plants were exposed to varying periods of direct sunlight in Singapore, it was observed that inflorescence production was dependent on the length of exposure to direct sunlight; those plants exposed longest flowered most profusely while those exposed to only four hours of direct sunlight daily did not flower at all (Goh and Wan, 1974).
Many Aranda hybrids are known to behave in the same manner. These plants require full sun for flowering and any shading would delay or suppress the process. In Aranda Wendy Scott, plants which received only three hours of direct sunlight (with eight hours of diffused and reflected light) remained vegetative, whereas those exposed for eight fours of direct sunlight (with three hours of shaded light) produced inflorescences regularly. When the former were transferred to eight-hour direct sun exposure condition, all the plants produced visible floral buds in seven to ten days and practically all the buds continued to develop to mature inflorescence (Table 2.)
The effect of light intensity on the flowering of shade-loving orchids is less obvious. These plants, such as Dendrobiums, Oncidiums, and Phalaenopsis, would not be able to tolerate direct exposure to tropical full sun, they would be scorched within hours if exposed to the strong midday sun directly. Even under partial-shade condition (with overhead green netting), the flowering behavior of Oncidium Goldiana was shown to have a ‘negative correlation’ with the sunshine hours two months before harvest by Pearson’s method (Ding, Ong and Yong, 1980).
Table 2. Effects of direct sunlight exporesure period on the flowering of Aranda Wendy Scott.
Direct Exposure Period
No. of Plants Treated
No. of Plansts Responded
No. of Florail Initials Produced
No. of Inflorescence Developed to Maturity
Experiment 1

3 hours
8 hours
Experiment 2

3 hours
8 hours
During the one month period, Floral initials in plants exposed for eight hours were produced within ten days after transfer from shaded conditions.
Temperature Effects
Low temperature has been shown to induce flowering in Cymbidium species and hybrids. Similarly, Phalaenopsis schilleriana requires a period of low temperature for floral induction (Rotor, 1952; de Vries, 1953). These are examples of vernalisation effect.
The effect of low temperature is also well known in another tropical orchid, Dendrobium crumenatum, the pigeon orchid. These plants produce inflorescences at intervals and flower buds are differentiated successively at the nodes of the inflorescence axis. However, the flower buds remain dormant at a very early stage of development. They start to develop again after a period of low temperature and bloom nine days later. This phenomenon, which can be described as thermoperiodism, has been examined for nearly a hundred years but the detailed physiological and bio-chemical processes involved are yet to be unraveled. It may be seen that low temperature may affect not only flower initiation but also flower development.
The periodic response of some orchids may be modified by temperature. For example, Cattleya gaskelliana grown at 18 oC (65 oF) flowered under long-day but not under short-day conditions; however, at 13 oC, they flowered under both long day and short day tr4eatments (Rotor, 1950; 1952).
Table 3. Some orchids requiring low temperature stimulus for flowering
Broimheadia finlaysoniana
Dendrobium Phalaenopsis
Cattleya Mosimae
Odontoglossum Citrosmum
Paphiopedilum Insigne
Dendrobium Angulatum
Phalaenopsis Schilleriana
Dendrobium Dendrocola
Sarcochilus Appendiculatus
Dendrobium Insigne
Thrixspernum Calceolus
Dendrobium Nobile

Some examples of orchids which require long temperature stimulus for flowering are listed in Table 3. The notable ones are the Dendrobiums and the cymbidiums. Indeed, Coster (1926) listed 15 species of Dendrobium which flowered eight days after the cold temperature experience; eight species including D. crumenatum after nine days; six species after ten days and three species behave the same way.
Hormonal Control
It is increasingly evident that environmental effects on plant growth and development are mediated through the changes in the levels of endogenous plant growth regulators (hormones). With Vanda Miss. Joaquim, it was found that the flowering intensity was inversely correlated to the auxin level in the shoot apex; plants that were exposed longest to direct sunlight and flowered most profusely had the lowest level of auxin, whereas those given only four hours of direct sunlight remained vegetative and had the highest level of auxin (Goh and Wan 1974).
In Aranda Deborah, decapitation induced flowering, but this response could be inhibited by a continuous supply of exogenous auxin (Goh and Seetoch, 1973) It was therefore suggested that the potential of flowering was present at all times. However, its expression was regulated by the endogenous auyxin level in the shoot apex. In other words, flowering is regulated by the correlative apical dominance effect. This suggestion is supported by the fact that application of a cytokinin (benzyladenine) caused production of multiple inflorescences. Similarly, anti-auxins and growth retardants were effective to stimulate flowering (Goh, 1977). These results indicate that auxin inhibits flowering in monopodial orchids.
In fact, the involvement of auxin in the control of flowering in orchid was suggested as early as 1953. With Phalaenopsis schilleriana, de Vries (1953) observed that plants sprayed with auxin solutions tend to be less abundant in flowering and suggested that there seemed to be an excess auxcin which inhibited the production of inflorescence under conditions in Bogor, and that the low temperature acted upon “an auxin controlling factor.”
Apart from auxins, other known growth substances are also involved. In our experiments with A. Deborah, high concentration of gibberellins (GA3, 10-4M) could cause the normal vegetative shoot apex to be transformed into reproductive growth to become a terminal inflorescence (Goh, 1979a). These reversions of vegetative growth and reproductive growths have been observed earlier in other monopodial orchids Arachnis Maggie Oei and Aranda Queen of Purples (Goh, 1976). Thus gibberellins may also have the role in flowering.
When the apices of Aranda Wendy Scott, a hybrid requiring full sun for flowering, were allowed to diffuse on agar for seven and a-half hours under the sun or shade conditions, no great differences in the amounts of diffusible auxins were observed, but the presence of inhibitors(s) were indicated under the shaded conditions by the Avena coleoptile straight growth method. The experiment was repeated with shoot apices from plants grown under different conditions: (a) sun, (b) transferred from shad to sun for 5 days and (c) shade. Three shoots (with seven leaves each) were tested in each sample and the diffusion period was seven hours. The results showed that more auxins diffused from shoots grown I the sun that that from the shade plant. The amount of auxin diffused from plants which were transferred from shade to sun remained low. Extractable auxins (after diffusion) were higher in shade plants compared to sun plants. On the other hand, diffusion or trans-location of inhibitor(s) appeared to occur faster (or greater) in the shade palnts, although inhibitor(s) was (were) extracted from all the samples. The diffusible gibberellins content from plants growtn under sun was much lower than that from plants grown under shade, whereas the reverse was true for extractable gibberellins extracted from the shoots after diffusion on agar.
While the bioassay showed changes in the level of endogenous growth substances occurred under different sun and shade conditions, it also indicated another possible mechanism in the control of flowering: inhibition by growth inhibitor(s) . It is likely that the inhibitor(s) contained at least in part, abscissic acid (ABA) which has a RF value of 0.5-0.7. Indeed, exogenous application of ABA to decapitated A./ Deborah inhibited the production of inflorescences (Goh, unpublished data). However, further studies are required to establish the role of ABA in the flowering of monopodial orchids.
With the sympodial orchids, our studies have shown that cytokinin can also induce flowering in Dendrobium hybrids, for example, D. Louise; D. Lady Hochoy and D. Buddy Shepler x D,. Peggy Shaw. The cytokinin effect is enhanced by simultaneous application of gibberellin (Goh, 1979; Goh and Yang, 1978). In these hybrids, however, auxin and consequently apical dominance effect are not likely to be involved since flowering can only occur in mature pseudobulbs which have completed their vegetative growth, their apices become dormant, and yet many mature pseudobulbs do not flower. Therefore, the requirement of cytokinin (and perhaps gibberellin too) may be involved more directly in the control of vegetative and reproductive development in these orchids.
Although it is believed that the environmental effects are mediated though changes in levels of endogenous growth substances, repeated attempts in our laboratory to supply Dendrobium crumenatum failed to stimulate further development of the floral buds; these buds responded subsequently to a cold night temperature treatment and bloomed nine days later. Thus, thermoperiodic control on floral development could involve more than changes, fir example, an increase in gibberellin level.
Gibberellins have also been reported to sitmulate flowering in Bletila striata (Sano et al, 1961), Cymbidium (Bivins, 1968, 1970) as well as Zygopetalum (O’Neill, 1958).
Flowering Gradient
Many Aranda hybrids, including A. Deborah, A. Hilda Galistan, A. Lusy Laycocok, A. Mei Ling and A. Nancy, exhibit a flowering gradient along the stem axis (Goh, 1975; 1977). In these hybrids when the axillary buds were stimulated to develop by decapitation, those near to the apex developed into inflorescens while the lower ones away from the apex developed into vegetative shoots, indicating that htflowering capacity was greatest near the apex and diminished basipetally.
Depending on the level of the decapitation, one or two seasons of response may be obtained. When the cut was near to the apex, the plants produced either inflorescence or a mixture of inflorescences then a second season of development occurred after the maturation of these inflorescence which took about seven months. The second response produced either a mixture of vegetative shoots and inflorescences or vegetative shoots only. When the cut was low, only vegetative shots were produced. Experiments with fully grown plants of about two meters in height showed that in A./ Lucy Laycock as well as A. Mei Ling, decapitation at 15th or 16th node (counting from shoot apex basipetally) still caused the production of inflorescences; in A. Hilda Galistan and A. Nancy, this level was found to be around 18th to 20th node. In A. Deborah, inflorescences were still produced when decapitated at the 25th node (Goh, 1975; 1977).
These observations had recently been extended to A. Pieter Ewart, A. Christine No. 1 (Koay and Chua, 1979) as well as Aranthera James Storie and Holttumara Maggie Mason (Koay and Chua, 1980). Since this orchids are in good demand in the cut flower trade, theabove flowering characteristics may be made use of in the commercial production of cut lfoewrs. In practice, these orchid hybrids need only be decapitated as close to the apex as possible and flowering will occur. This decapitation method is essentially for a once-a-year crop. However, continual production is not only possible but feasible in a large nursery where plots of plants can be rotated in such a way that inflorescence production can be scheduled on a monthly basis or to meet seasonal demands. Practical details and laternate methods have been discussed earlier (Goh, 1978).
Concluding Remarks
In view of the fact that Orchidaceae is not only large in number of species (and there are thousands and thousands of hybrids), but also wide ecological distribution, it is not surprising that the factors controlling flowering are so variable. The available information is still very limited compared with those on some other horticultural crops like chrysanthemums or tulips. Nevertheless, it is seen that a certain degree of control is possible, at least in some of the commercially important species or hybrids. More work on the physiological aspets would certainly enhance our understanding and perhaps in the not too distant future, we will be able to regulate the flowering or more orchids.
Literature Cited
Arditti, J. 1979. Aspect of the phuysiology of Orchids. Adv. Bot. Res., 7, 421-655.
Bhattacharjee, S.K. 1979. Regulation of growth and flowering in Cattleya orchids by altered daylengths. Singapore J. Primary Industries, 7, 90-92.
Bivins, J.L., 1968. Effect of growth regulating substances on the size of flower and bloom date of Cymbidium Sicily ‘Grandee’ Amer. Orchid Soc. Bull., 37, 385-387.
Bivins, J.L. 1970. Effect of Giberrelic acid on flower size and bloom date of Cymbidium Guelda, Amer. Orchid Soc. Bull., 39, 1005-1006.
Coster, Ch., 1926. Periodische Bluteerscheinungen in den tropen. Ann. Jard. Bot. Buitenzorg, 35, 125-162.
Curtis, J.T. 1954. Annual fluctuation in rate of flower production by native cypripediums during two decades. Bull. Torrey Bot. Club., 81, 340-352.
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Fertilizer Requirements of Orchid Plan

Fertilizer Requirements of Orchid Plan

Written by [Philippine Orchid Review]
Tuesday, 01 October 1985
How often should orchids be fertilized? This, of course, defends on the genus, the amount of sunlight it gets, temperature conditions, general condition of plant, and whether or not it has good roots. It is useless to fertilized heavily, or fertilizer will not produce roots. Fertilizers with nutrients are more conductive to the production of the numerous than those with an abundance of nutrients. In the cultivation of orchids, it is well to keep this in mind if one is to have a happy medium between vegetative plant growth and root growth; too many roots may indicate insufficient fertilizer or lack of moisture. The more sunlight the receives, the more fertilizer it can assimilate. Over fertilization of orchid can be just as detrimental to the quality of the flowers as under fertilization.
Scientific studies had provided us with the knowledge of which elements are necessary for proper plant growth, and, in turn, this as been useful in determining the percentages of nutrients to use it as fertilizers. We know the nitrogen, phosphate and potash are elements used in the greatest quantities, but there are other elements which are equally important such as boron, manganese, iron, zinc, copper and molybdenum. The lack of anyone of these will cause improper growth, either in flower or vegetative growth.
Too much of nitrogen will produce soft growth and the flowers of poor quality; too much potash and phosphate will produce small flowers. With seedlings since the first goal is to produce a good plant not flower – more fertilizer can be applied than the mature plant where fine flowers is the main objective.
When there is an over – abundance of nitrogen, it will be observed by the plants and damage the roots. If the root of orchid plants are damaged, water will have to be absorbed through the leaves a very slow process.
Fro time to time we are advised to fertilize orchids by spraying the leaves with fertilizers. Occasional light that foliage feeding in conjunction with the application of the fertilizer to the growing orchid plant is permissible, but should not be relied upon as the sole means of supplying all the necessary nutrients the plants needs. The fact that most orchids are epiphytic does not mean that they do not absorb nutrients from the roots. Therefore fertilizer should be applied through the potting medium rather than through the leaves if satisfactory culture is to be achieved. In fact, accumulation of fertilizers on the leaves of orchid plants can be harmful because photosynthesis ( the manufacture of food ) is prevented.
Since we have of abundance of sun and warm temperatures most of the year, nitrogen is generally limiting factor. So the use of fertilizers having 30-10-10 analysis during the greater part of the year is acceptable practice. To prevent soft growth and to increase production of flowers, fertilizer with 20-20-20- is often use on mature plants. Some orchid growers use fertilizer with high phosphate and potash content – for example 10-30-20. Such a formula is advantageous to induce flower production in Vandas, Dendrobiums and most generally grown in this country.
Remember – to fertilized orchids is a necessity, but it is far better to fertilized too little than too much.

How I Pot Orchids

How I Pot Orchids

Written by [Philippine Orchid Review] Andres Golamco, Jr.
Tuesday, 01 October 1985
Ever since I started raising orchids about 15 years ago my goal has been to grow the plants into large specimens in pot and enjoy them indoors when they are in full bloom. And potting the orchids in the best way should be considered.
So, I have been experimenting with various media, and the best medium that suits my environment and treatment is charcoal. But every year, Especially right after the rainy season, when the algae covers the potting medium, the plant’s growth become smaller and the roots begin to rot. To improve the plant’s condition, I have had to repot the plant into a fresh medium a new pot.
Year after year, I have found my self-repotting more plants, which no longer produce good growths and roots. Having more plants to repot, I have decided to remove the charcoal pieces that occupy the bottom part inside by the pot by enlarging the bottom drainage hole to two inches or three inches in diameter for the pieces to pass through, leaving only less than one half of the original potting medium content of the upper surface intact, and then returning the plants back in their places
After one year, it is surprise to find the plants with accelerated growths and find the roots spreading inside and outside the pot. Impressed by this unexpected discovery, I have decided to pot all the plants in this manner but with some slight variations. To make the plant stand up, I use a good and strong wire-stake and securely tie the base and the middle portion of the plant and place. Then I position the newly stake plant where its latest growth has room to grow and use about three or six charcoal pieces. (1” think times 2” – 3 long) to anchor the plant.
The charcoal pieces have to be fitted carefully such that the base pf the plant tightly secured and does not allow any movement otherwise. The plant cannot root properly and the roots get damaged every time the plant moves.
Using this technique for five years now, I have found that several plants show improved root and bulb/stem growths. Upon flowering, these plants produce outstanding blooms. I have also discovered several advantage in using this method:
I can now water everyday without fear of over-watering the plan.
With fewer charcoal pieces only to serve as anchorage, I use less potting medium and therefore cutting expense.
With more air spaces, air can feely circulate through and reach the roots.
With less medium, the roots are cleaner and healthier without problems of rot or decay.
The fact that there is less medium, the roots have more room to grow and spread out freely.
With good system, the plants grow larger and robust, thereby producing flowers of superior quality and long life.
A very important one, the plant could be grown to specimen size quickly.
Several of my plants are now approaching specimen sizes and I am quite pleased that I have discovered a very effective method, to reach my goal. Using this unique method, I could now grow orchids in pot with good root system and vigorous growths into the best-looking specimen plants.

Tree Fern as Potting Medium

Tree Fern as Potting Medium

Written by [Philippine Orchid Review] Vicente Chin
Monday, 01 April 1985
Tree fern is a tedious medium to use for potting orchids, but the results are very satisfying because it encourages abundant rooting and deteriorates quite slowly (2-3 years). Cattleya orchids especially favor this medium for potting.
Tree fern need to be chopped (1”), shredded, and washed thoroughly before it can be sued for potting orchids. For additional safety, it should be boiled or soaked in a 10% chlorox solution for pasteurization. Tree fern requires plenty of rinsing before the water becomes clear.
Ideally, the coarser fibers are used for bigger plants while the finer-textured fibers can be used in seedlings or semi-terrestrial orchids or other orchids that like more moisture.
To obtain excellent drainage and aeration, the pot should be filled from ¾ to ½ full of big size charcoal. Your local microclimate will determine how thick a topping of tree fern you should use. Dry and windy areas will use a thicker layer of tree fern, while shady and humid areas will require a thinner layer.
Fibers can be aligned either vertically or horizontally, depending on your local climate. Vertical arranged fibers will allow faster drainage.
It is important to pack the fibers very firmly for cattleyas and vandas, but it should not be so tight that you injure your hands or the rhizomes in packing the fivers. Make sure that you finish potting with the surface of the medium very level. Uneven surface will produce crooked rhizomes in cattleyas. Pull out and re-insert fivers that stick out from the surface.
Compare to all charcoal potting, the tree fern topping lessens the frequency of watering. Be careful not to over water. Fill the inside through the bottom hole for moisture or inspect the pseudo-bulbs for shrinkage before you water.
Regular feeding should allow until the plants established or when new roots are starting to come out. Feeding must be very light initially (1/4 strength) and later increased as more roots are developed.
For convenience, slow – released fertilizer granules ( Gaviota ) may be use once the plants are fully established. Use only 1/4 to ½ the rate recommended for terrestrial plants every three to four months.
Very young orchid are safe with foliar feeding because there are more susceptible to burning ( over fertilization ) by the use of slow release-fertilizrer.
Experience will guide you whether more or less fertilizer can be use by the plants. Exercise caution because orchids are easily killed by over use of fertilizer.
Take care not to expose this medium to constant moisture as algae will soon invade this medium. Adequate protection from continuous rains with plastic sheets framed over the branches will lessen the change of algae infestation.
Slight drying between watering as well as regular Physan spray specially during rainy season should help prevent algae.
It must be admitted that this medium is rather tedious, but it help me to consistently grow quality plants fit for exhibition/competition.