Dec 22, 2006

Orchid Farming


The different species of the Orchid family require different methods of cultivation. It is thus, necessary for a would-be orchid enthusiast to have initial information to guide him raising orchids.

Cattleya.

The term is used to cover a very large variety of species of Cattleya, Laelia, Brassalova, a few species of Epidendrom, Sophronites, Diacrum and their hybrids.

Most cattleyas in nature are found in trees, in fairly exposed positions and very rarely in heavily shaded areas. The plant thrives well in fairly high humidity. They like light breeze in moderation and a good amount of sunshine. Exposure to the morning sun is good to the plant .

Osmunda, charcoal, or their combination are the commonly used potting mediums. Osmunda is long-lasting and has natural nutrients. However, it attracts insects since it holds water well and takes time to dry. Charcoal dries fast and supplies the right humidity for all genera. however, it has no nutrients and is prone to salts.

Usually orchids have to be reported every two years either because the plant has outgrown its container or the potting mix has rotted and needs to be replaced. The ideal time, however, is just as plants grow a new roots and immediately after blooming when the plant is dormant and cannot be seriously disturbed.

The following procedure of repotting applies to all orchid species:

* Run a thin knife blade under the roots, outside the pot to loosen them. Repeat the process on the pot.

* With a strong knife or screw driver, pry the plant upward and out of the pot.

* Remove all decayed potting materials and dead roots, leaving only live roots.

It is also good to clean the plants. Remove the papery bulb sheaths; cut off dead bulbs, leaves and any injured or rotten spots on the leaves. Dust all cuts with fungicide. check the plants for insects on the underside of the leaves, along the rhizomes and between the joints or rhizomes and bulbs.

Here are some requirements for good repotting:

Container and potting medium must supply good drainage and ventilation.

Plants must be potted tightly so they are held firmly in place.

Plants should be repotted with enough growing space for two to three years.

Rhizomes should be buried halfway into the potting material so that it will not rot.

Feeding Cattleya with fertilizer is essential when the eye is growing into a mature pseudobulb and leaf. during dormant stage, avoid feeding since this disrupts their natural cycle of flowering; flowers may become weak or not bloom at all. Better underfeed than overfeed it.

Cattleya does not do well during drought. If deep wrinkles appear three or four bulbs back, if there are wrinkles on the new bulb and the leaves are soft, the plant badly needs water. However, if the bottom of the pot is moist, don't water.

An orchid grower must be alert to cause and signs of disease in cattleyas.

Extreme sunlight, overwater, sour potting material, and poor drainage results in the yellowing of the foliage. Overwatering which causes the roots to rot, underwatering, orchid scale damage, and low humidity results in the shriveling of the leaves.

Low humidity and overwatering also causes poor rooting and bud blast (buds turning soft, watery and shriveling before maturing). Poor ventilation causes bud blast, too.

Water allowed to evaporate on the bloom leaves spots on the bloom. No droplets of water, therefore, should stay on the bloom after watering in the morning, Sunrays on water droplets result in small burn marks.

Slow unfolding of foliage is due to lack of sunlight, poor ventilation and loss of roots. Failure of cattleya to form sheaths or buds is caused by too much sunlight or lack of it, shock from repotting and sour potting material.

Watering late in day, overwatering, poor drainage and setting pot on water causes rotting; poor ventilation and low humidity causes rotting; poor ventilation and low humidity causes short-lived blooms.

Phaleanopsis.

Popular known as the Butterfly Orchid this plant can give sprays flowers the whole year round.

Butterfly orchid requires high temperature, fresh air and moist surroundings. It prefers shade since the sun easily burns its fleshy, soft leaves. About 40 per cent shade will produce the best results.

This orchids can be grown on tree stumps, shallow wooden baskets or spots. When repotting, cut the roots adhering to the outside of the pot. Lift plant out of pot and remove all the potting medium and drainage material. With a pair of scissors dipped in Chlorox or a similar solution, cut long and decayed roots. Fill one-third of the new pot with charcoal. Put the plant in it and wash the rough compost between the roots. Make sure plant is aired and lamp. When mounting on tree stumps or basket, use coconut husk or osmunda to give plant more dampness.

Butterfly orchid has very soft cell structure that burn very easily when directed in contact with fertilizer. Thus the plant must be watered before fertilizing; use only half the strength of fertilizer recommended. The plant should not be allowed always. Place the orchids away from path of direct draft.

Butterfly orchid is prone to red spider mites which attack the underside of the leaves. Use miticide to control the mites. Mealy bugs are also serious pests when new spikes begin to produce buds. Common problem in growing butterfly orchids are: leaf rot caused by infection, insect damage, wet condition at night and poor ventilation; bud rope due to abrupt changes in temperature and cultural condition, air pollution, and application of insecticide or fungicide during budding stage; crown rot caused by overwatering; and dropping of major leaves due to stem borer insects.

Dendrobium.

The orchid is classified into three sections based on cultural requirements. However, only two types are featured here since they are the common types grown in the Philippines.

* Dendrobium Phaleanopsis has deep rose with magenta lips like the phaleanopsis bloom. This type grows from March to August and needs warm, moist surrounding with 65 per cent light. It is also prone to bud drop due to abrupt temperature change and air pollution.

Dendrobium is planted in small clay pot 3 to 4 inches in diameter or mounted on tree stump. Charcoal, gravel or volcanic cinder is used as potting medium. If tree stump is preferred, simply plant to the tree securely.

Feed only during months; stop fertilizing when new growth has been completed.

Regular heavy watering , twice a day during summertime, is necessary especially when roots of new growth appears. During flowering, little watering is required.

* Cane-type Denrobium is an epiphyte and semi-terrestrial garden plant that bloom with long arching sprays. It likes warm weather and 85 per cent of sunshine. It is a strong grower hence it needs heavy feeding especially during its growing period.

In watering this type, follow same schedule of other dendrobiums.

Vanda.

This is classified into two lea types- the terete (and semi-terete) and the strap-leaf.

Terete and semi-terete Vandas are light - loving plants and produce a good crop of flowers when grown in full sun.

The strap-leaf Vanda is grown in shaded areas to counter-act yellowing of the foliage due to too much sun.

Osmunda should not be used on stress; putting Vanda in a wooden basket is better. It is important for root to have free access to air. Roots must be prevented from attaching with other plants, branches, etc.; wet roots and bend them back towards container.

To plant, insert tree fern strip 4-5 inches in diameter to support this tall plant and its roots which appears high up on the stem. If plants becomes too tall, the top with two to three roots can be potted as a new plant.

Vanda is heavy feeder; follow general rule for feeding.

Scale insects, weevil and snails are the common enemies of Vanda. Insecticide given once a month should provide enough control. Use often as needed if plant is prone to insects.

Keep track of symptoms of common problems: yellowing and loss of leaves, loss of roots and lack of humidity; crown rot caused by over watering , failure to bloom due to inadequate light and food; and leggy plant caused by inadequate light and defective root system.

TISSUE CULTURE

Thousands of identical orchids can now be produced in just a short time from a single small mother tissue. This is made possible through the tissue-culture technique, a process of growing an active part such as bud or shoot tip in an artificial environment.

The use of this technique in the ornamental and cut flower industry can helping a growing market. The time needed to establish a cut flower business will also be reduced. With this technique, new and potentially good varieties can be introduced early, reducing the long and expensive years of selection for producing new cultivars. Moreover, the technique is particularly useful in producing virus-free plants.

Before carrying out tissue culture, test the plants for possible presence of viral pathogens to prevent their transfer to the culture.

Initial implementation. Implant a well-chosen active growing point or tissue (shoot tip, bud, cotyledon) dissected from a young growth. In Dendrobium, this is taken from the young shoot arising from the rhizomes.

A suitable medium- solid or liquid- on which the tissues will be grown should be chosen. Nutrients needed in the tissue culture medium vary with the kind of plant and the type of development desired.

Multiplication. The plant materials in the form of callus tissue are then replanted in separate culture bottles. As multiplication continues, separate the tissues and reflask into another bottle to produce more growth. Here, the medium is usually solid. Cultures at this stage are subjected for the treatment for shoot development.

Preplanting. From the crowded culture bottle, transfer the growing tissues to a medium without hormones and expose them to more light. This will allow the seedlings to harden, develop good quality and take root before transplanting to pots.

Composting and seedling care. When leaves and roots are fully developed, transfer the seedlings from flask and plant them in sterilized fine osmunda fiber. They should be places in an area with higher relative humidity and uniform moisture to prevent them from drying out. Fertilize the seedlings with weak solution of complete fertilizer to hasten their growth until they are already for single potting.

Plants produce from tissue culture are easily transported because they can be placed in flasks. Valuable ones can be maintained indefinitely in a medium, deposited in a genebank and withdrawn when needed.

Since tissue culture is possible only in a laboratory, try looking for a commercial orchid laboratory that provides professional tissue culture services. One such laboratory is Thanawadee's Orchid World, Inc. in Metro Manila.

Tissue culture generates cost savings of 60 per cent over embryo culture, which means a savings of P8.72 per plant. It is also more economical than vegetative division by 34 per cent with a saving of P2.80 per plant.

With tissue culture, cheaper and high-quality seedlings can be made available through seedlings can be made available through contract growing.


Source: DOST, photo courtesy of http://www.sunsetvalleyorchids.com, http://www.doweryorchids.com

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