Wednesday, December 05, 2007

Orchids (part1)


Description:The Orchid family is the most numerous family of the flower plants and the most stunning and elegant family of flowering plant known to man. It stands for more than 25000 species worldwide. There are many kinds, some living over other plants, specially trees - ephifytes-, other are lianas or just terrestrial.
Some species are saprophytes - without chlorophyll - feeding themselves from the humus they are living on.Cultivation and careIn the world of the orchid, temperature, light and humidity work in conjunction with one another, and unless a harmonious relationship is achieved between them, optimum growth is not possible. In instances of low humidity, high temperatures can be dangerous; in the case of too much atmospheric moisture, the effects of low temperatures can be over-emphasized. A widely held misconception is that all tropical orchids need extremely high temperatures to survive. This is not altogether true, and to subject them to such treatment can be disastrous.LightLight is a key factor in growing healthy orchids. Direct sunlight may cause plants to burn, and too little light will prevent plants from flowering. An ideal location is behind curtains or window blinds. Leaf color is a good indicator of the amount of light a plant is receiving. Orchids should have bright green, healthy leaves. Dark green leaves indicate that a plant is getting insufficient light, and yellowish-green or red leaves indicate that a plant is getting too much light. If you suspect a plant is exposed to too much light, feel the leaves. If they feel noticeably warmer than the surrounding air, move the plant to a location with less intense brightness. Low light orchids enjoy a north or an east, protected west or shaded south windows of the home. Standard household temperatures are adequate. Orchids that are classified as low light, warm growing are: Paphiopedilum or Lady Slipper, Phalaenopsis and Oncidium.Moderate to high light orchids like warm household temperatures. They thrive in a west or south window. From early May to late September, you should watch light levels in south windows to avoid burning; you may have to move your orchid away from the window or place them behind a sheer curtain to decrease light intensity. These orchids like to dry between watering. Orchids that are classified as moderate to high ligh are: Cattleya, Dendrobium, and Vanda.A. Phalaenopsis hybrids enjoy the light behind curtains and window blinds in this master bedroom.B. Too much light can permanently sunburn the orchid leaves.C. A good way to tell if a plant is receiving too much light is by feeling the leaves' temperature.D. Masdevallia veitchiana is by nature cool-loving and suited to cultivation only in cool places.TemperatureTo produce beautiful, long-lasting blooms, orchids must produce energy in the form of carbohydrates during the day when the temperature is high and store that energy at night when the temperature drops. This temperature fluctuation is necessary for orchids to bloom. Without a day-night fluctuation of 10-15 degrees Fahrenheit, the plants will grow plenty of healthy foliage but may stubbornly refuse to flower. A night temperature of 60-62 degrees F is ideal for optimum growth, but temperatures as low as 55 degrees F will not harm your plant. Daytime temperatures should range between 70 and 80 degrees F. Temperatures as high as 90-95 degrees F for short periods will cause no harm, however, as long as proper humidity and air circulation are maintained.HumidityOrchids love humidity, so the ideal daytime humidity for orchids is 50% to 70%. During the summer, when the days are warm and dry, humidity can be increased by placing plants in a shallow dish or tray containing pebbles and water. Be sure to keep the later just below the tops of the pebbles. Never let water touch the bottom of the pot; capillary action will expose the roots to too much water, causing them to deteriorate. To maintain the quality of water in the tray, remove the pebbles every 2 or 3 months and wash them in a weak bleach solution to remove accumulated salts and algae. You can also group your plants together in a single evaporation tray to create a humid microclimate and an attractive display. Just don't place them so close together that air circulation is restricted.As a general rule, it must be stressed that both temperature and light should be taken into consideration when deciding to increase humidity. Any form of watering, damping down or spraying should not be performed in the late afternoon or evening. Although some growers obtain good results with this method, beginners should avoid the practice. The falling temperatures toward the end of the day can cause unnecessary condensation if highly humid conditions are induced; plants will then become covered with a film of water droplets, which can lead to rotting.AirIn the wild, gentle continual breezes along the leafy canopy of the rain forest are vital for the survival of orchids and other air plants. Air movement acts as preventive medicine for orchids. It helps evaporate stagnant water, trapped during watering, where fungi and bacteria breed. Without ventilation or fresh circulating air, orchids eventually die from rot, lack of a continual carbon dioxide source, or infection. Ventilation also helps orchids tolerate intense light without getting burnt leaves.

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