Tropical Orchid World

Growing Orchids

Orchids are also one of the most adaptable plant groups on earth. Some Australian orchids grow entirely underground, and many tropical jungle orchids grow in the upper branches of trees. Tundra, rainforest, mountain, grassy plain, desert and swamp environments contain numerous orchid species.

Orchids produce seed pods with literally hundreds of thousands of seed that are released and scattered by the wind. Orchid seeds must establish a symbiotic relationship with a special fungus to survive its first year of life. The fungi gathers water and minerals for itself and the seedling, and the seedling shares its sugars from photosynthesis with the fungus. Only one or two orchid seeds will ever germinate and survive on that perfect crevice or depression that is both moist and has the fungus present. Even then, its chances to survive in the wild long enough to bloom are slim.

To avoid this problem, greenhouse growers sow orchid seeds on moist, sugar-rich, sterile agar, or they cut out growing clumps of orchid cells and place them on the agar. These techniques allow many hundreds of orchid plants to survive to maturity. New and improved hybrids can be mass produced rapidly. This is important as orchids are very slow growing. Many orchids take five to seven years to mature to flowering. You can see why breeding three or four orchid generations could span a person's lifetime just to get one new hybrid propagated sufficiently for sale.
Classification

All orchids belong to the Orchid Family, Orchidaceae (or-Kid-ACE-ee-ee). Orchids are divided into two basic growth types: monopodial and sympodial. Monopodial orchids have a central stem which grows continuously from the tip. Flowers are produced from the stem between the leaves, usually alternately from side to side. Phalaenopsis orchids are a good example. Sympodial orchids, such as cattleyas, laelias and paphiopedilums, possess a rhizome which sends out a shoot. This develops into a stem and leaves and eventually produces flowers. In time, from the base of this growth, a new shoot develops and so on in a continuous cycle. The buds are often, though not always, protected by a sheath.

The mid section of stems of sympodial orchids are often expanded into water-storage organs called pseudobulbs. These vary greatly in size and shape, ranging from tall and pencil-thin to bulbous and onion-like. The leaves vary too, some being soft and folded like a fan, others thick and leathery. The roots of epiphytic orchids have an outer layer or corky cells called velamen, which protects the thin, living cortex within. These adaptations allow orchids to absorb water and nutrients rapidly from raindrops, but protect roots, stems and leaves from water loss during dry periods. Most orchids are adapted to conserve water and should be cared for as such.
Orchid Cultural Requirements
Growing Medium

There are many different types of orchid potting medium used in orchid culture. The overall consideration is to provide structural support for the orchid roots, but also to provide lots of air spaces between medium particles. Many orchid plants are grown in osmunda fiber. This fiber comes from the roots of the Osmunda fern that is native to Australia and the Pacific. The tough, wiry fibers break down very slowly and is an ideal potting medium. Fresh pine bark is also a popular medium but is usually mixed with other amendments before use. Both materials are sometimes mixed with peat and perlite or vermiculite. Some orchids are even grown in pebbles mixed with bark. Most orchid roots are adapted to being exposed to air and harsh conditions, but cannot tolerate being wet for more than a day or two.

Orchids grow slowly compared to houseplants. However, most orchids need to be repotted about once every two years. To pot an orchid, the pot is filled about two-thirds with orchid potting medium, then the plant is set in the pot with its roots spread out. The growing tip either centered (monopodials) or placed two fingers from the pot rim (sympodial). Then additional media is packed tightly around the plant to hold it in place. You should be able to turn the pot upside down without the orchid or medium falling out. Practice will insure successful repotting. When the plant outgrows the pot by extending the new shoots over the edge, usually about every two years, it is time to repot.
Light

The ideal place in the home for growing orchids is a bright window, free from drafts, where your plants receive indirect sunlight both morning and afternoon. (A south window is best.) In winter, give orchids all the light possible. Light intensity should be between 1500 and 2000 foot candles the equivalent to a bright south-facing window. With extra large windows or especially intense sunlight, the light may be adjusted downward by moving plants 18 to 36 inches from the window. Plants in the home require a greater light intensity because they receive light from only one direction, while in a greenhouse they receive light from many sides.

Many orchids can be grown in a greenhouse or outdoors. All will require partial shade. Therefore, it is best to shade the section of the greenhouse you intend using or else grow them in an area that you have already shaded for foliage plants or African violets. Dendrobium Oncidium and Vanda will grow best in 20-30% of normal outdoor light, whereas Phalaenopsis-type orchids require only 10- 15 % of normal light.
Artificial Light

If you have neither a greenhouse nor the proper windowsill conditions, fluorescent lighting provides good results. You can grow and flower many types of orchids in the darkest basement or shadiest apartment with the addition of just one shop light. Most orchid hobbyists find having at least four 36%u2033 or 48%u2033 fluorescent tubes provides excellent light levels. Each group of orchids (primarily those with low to medium light requirements) will need a minimum of two forty-watt fluorescent light tubes hung six inches above the plants.

Keep lights on for a minimum of 12 hours per day in order to provide the minimal amount of light necessary for proper growth and flowering. If you are able to place your fluorescent light setup near a sunny window, your orchid flowering chances will increase. The best type of fluorescent tubes seem to be those designed specifically for plants.
Humidity

Potted orchid plants may be set on decorative pebbles in a water-filled tray, saucer, or other container. Evaporation of water from pebbles provides humidity. Pebbles also make the growing area more attractive, while assuring good drainage. Mist your plants with distilled water because tap water can lead to salt deposits on the leaves. A plant which is kept soaking wet invites attack by bacteria and fungal diseases. If you are able to enclose an area like a greenhouse, you will find it easier to maintain a proper humidity.
Temperature

Orchids are not as delicate and temperature sensitive plants as most people think. Most will adapt readily to conditions offered by any home or greenhouse. For growing purposes, we group orchids into three temperature classes:

The medium temperature class is represented by many Cattleyas, Epidendrums, Oncidiums, and Laelias, and most other commercially available orchids. The ideal minimum temperature is 60 degrees F nights and high 70s during the days. An occasional deviation will have no harmful effect. This group will do very well with the air, temperature, and light facilities found in the average home.

The cool class includes Cymbidiums, Cypripediums, Odontoglossums and Miltonias, and should be grown 5 degrees to 10 degrees F cooler than the medium class. These plants also require high light, so imagine cool, sunny October mornings as an example of the light and temperature that this class needs.

Warm class orchids are represented by Phalaenopsis, Paphiopedilums, Vandas, Rhynchostylus and Dendrohiums. These plants should be grown 5 degrees F warmer than those in the Medium Class. They do well in high humidity and can be grown outdoors in Georgia from late spring to early fall if shaded and protected from rain. Never expose orchids of this class to less than 45 degrees F.

During cold, freezing night temperatures, all orchid plants should be moved away from the window to provide a protective airspace against freezing. Air temperature can be 15 to 20 degrees F cooler near the windows than the room temperature.
Watering

Watering is the most important factor in orchid culture. A good rule of thumb is to water whenever the medium (osmunda fiber or bark mix) is dry. If you grow the plants in pots suspended in the air, they will dry out more rapidly than bench grown plants and will need watering more frequently. Orchids potted in bark require more frequent waterings than those in most other potting media, just as plants in clay pots require more frequent watering than those in plastic pots. Orchids may be grouped into three categories according to their moisture requirements.

Low Water Use. Cattleyas, Laeliocattleyas, Brassolaeliocattleyas, Oncidiums, Miltonias, and Odontoglossums are ephiphytes or "air rooted" orchids, with built-in "water tanks" or pseudobulbs. They should be allowed to dry out slightly between waterings so air can circulate between the epiphytic roots. Water every five days or so. In the heat of mid-summer, water may be needed every three or four days. During the short, cool days of winter, increase the time between waterings to 10 to 14 days. If you do err

Vanda denisoniana

This is the one of tropical orchid, whit yellow flower it's look really bright and clean, This speciese is have the smell at night . really good smell