CULTURE CORNER: ORCHIDS
A big thanks to the American Orchid Society for giving their permission to post the following easy-to-follow growing information for specific genera/conditions. Visit their website http://www.aos.org for additional information like pests and diseases, greenhouses, photo grids and many more.
Keep in mind that they are Norhtern hemisphere (seasons are different) and that the temperatures must be converted to Celcius.
Printable Culture Sheets (PDF)
PESTS & DISEASES
Thanks to Sue Bottom of the St. Augustine Orchid Society for the following very informative article on Orchid Pests and Diseases:
For environmental conditions:
Culture: Pests and diseases – pdf download:
Orchid plants are becoming increasingly fashionable as decorations in homes, offices, hotels and other living areas. This trend is also reflected in the media and makes perfect sense as the use of flowering orchid plants creates a natural and stylish effect.
These exotic plants have at last become more freely available and the many varieties are easy to grow and extremely long lasting.This huge plant family offers something for every taste. The variation of colour, shape and size is endless and there are even fragrant orchids that fill your home with a sweet and subtle scent.
Orchids are easy to grow – don’t be told otherwise. Large parts of South Africa have an ideal climate to grow most of the popular orchids available. You just have to remember that the majority of orchid types which are cultivated do not grow in soil.
Although a few terrestrial (ground) orchids are in cultivation, most of them are epiphytic. They grow in trees or on rocks (litophytic) and have a greater part of their root system exposed to light and air. For success these conditions must be copied in cultivation. To do so plants can be grown on slabs of tree fern, cork bark, sekelbos, hardekool, bobbejaanstert, coconut shell or husk etc. They can also be planted in pots or baskets with a coarse potting mix. This ensures a high volume of air within the pot and free drainage of water.
A rule of thumb is that the heavier and thicker the root system, the coarser the mix. A number of prepared mixes are available using pine bark chips, macadamia shells or cultiwool as a base. The chips should be 5 mm to 20 mm in size and some additional components can be added to keep the mix open and aerated like polystyrene, foam chips or genulite (perlite) .
Cattleya: Warm to intermediate growing. Allow plants to dry out between watering.
Cymbidium: Like lots of fresh air and filtered light. Water frequently during hot weather.
Phalaenopsis: Prefer darker and warmer conditions. Feed regularly.
Paphiopedilum: The slipper orchids prefer more shade. Dilute fertiliser to half strength.
Nobile types: Can take full morning and afternoon sun and only need light shade during the hottest part of the day. Lots of water in summer – occasionally in winter.
Dendrobium Phalaenopsis types: Grow in warmer conditions like Phalaenopsis.
Epidendrum: Very easy to grow. They need a lot of light and flower all year round.
Miltoniopsis: Thrive in intermediate climatic conditions, some shade and regular watering.
Odontoglossum-Alliance: Cool to intermediate conditions with strong light, sufficient air movement and high humidity.
The majority of orchids grow in a moderate climate with lots of fresh air and humidity.
- Provide 50 to 60% shade – most orchids thrive in diffused bright light.
- Symptoms of too much light can be pale yellow leaves or red pigment appearing in streaks and round the edges of the leaves.
- Too little light may result in soft dark green foliage and plants that do not flower well.
As a general rule plants without pseudobulbs (like Phalaenopsis, Paphiopedilum etc.) do not want to dry out totally between watering. Plants with pseudobulbs (like Cattleya, Oncidium, Dendrobium, Cymbidium) need to dry off between watering.
- Keep plants moist but not wet. Once or twice a month, plants should be flushed with water to guard against fertiliser burn. Apply more water in hot conditions – less when cold.
- Orchids should not stand in water – For extra humidity plants can be grown on pebbles in a tray with water, but the pots should not touch the water.
- Mounted plants should be watered more regularly.
Some orchids (like nobile Dendrobiums) require a winter rest period with light misting instead of watering and feeding.
Apply any balanced pot plant fertiliser like 18-18-18 weekly. Higher nitrogen (30-10-10) can be used in the growing season (Spring and Summer). A fertiliser specifically for Orchids is available from nurseries.
When the plant outgrows its pot or the potting medium breaks down, it is time to repot. The best time for repotting is just after flowering when the new roots start to develop. Good drainage is imperative. The container must not be too large.
Chopped pine bark or Macadamia shells mixed with a small amount of polystyrene, cultiwool, sponge or Genulite provides a well drained mix. Add a sprinkling of dolomitic lime – N.B. No soil! Tree fern, cork, sickle bush (Dicrostachys cinerea) and Xerophyta (villosia or bobbejaanstert) make excellent mounts
GROWING ORCHIDS ON MOUNTS – An abstract from the SAOC bulletin by Tinus Oberholtzer
When growing orchids, we have to try and replicate their natural conditions and environment. As most orchids are epiphytes in nature, the most natural way of growing these would be attached to a piece of wood rather than growing in a pot. A wooden mount would therefore be any piece of wood used as a ‘host’ or ‘support’ for your orchid plant to grow on. In Europe and the U.S.A many growers use cork bark or cork branches as mounts for their orchids as the bark is quite coarse with lots of place for the orchid roots to attach and it lasts quite long.
Natural cork is not as freely available in South Africa so not used as often. But there are two important factors to learn from the use of cork as a mount: the need for a coarse substrate and something that will last long.
Most orchid roots will not attach too well and grow at their best on a smooth surface so the coarser the bark on the mount, the better. Select wood which will last for a few years as you do not want to disturb the plant too often.
GROWING ORCHIDS by Angela van Rooyen – For a more comprehensive article on orchid culture
TREES FULL OF ORCHIDS by Linet Hamman
Repotting – LINKS
Repotting Orchids. Repotting an orchid for the first time can be daunting. Repotting an orchid. Although it isn’t a difficult task, it is sufficiently …
www.floridagardener.com/misc/RepottingOrchids.htm – 17k – Cached – Similar pages [PDF]
Because orchids grow differently than regular plants, repotting an orchid means taking a few extra steps. Here’s how to do it.
www.rv-orchidworks.com/cultivate/care_repotting.html – 14k – Cached – Similar pages