Each lesson culminates in an assignment which is submitted to the school, marked by the school's tutors and returned to you with any relevant suggestions, comments, and if necessary, extra reading.
Why Grow Orchids?
The climbing genus Vanilla,(there are over 100 species in the vanilla genus)- has one very well-known form- Vanilla planiflora- the source of Vanilla flavouring (from the pods).
Tubers from some genera (e.g. Orchis, Dactylorhiza & Eulophia) are used in a dried form in parts of Europe and Asia for medicinal and culinary purposes.
Many orchid genera are important as ornamental plants, cultivated as indoor plants, greenhouse plants and cut flowers. Some are grown in pots or the ground out of doors, even in cooler climates; though the greatest use as an outdoor plant is in the sub tropics or tropics.The genus Cymbidium is for example, the most widely grown in southern Australia.
What Conditions Do Orchids Need?
The amount of watering will depend on the species, the season, temperatures, wind / protection, the natural rainfall, and the stage of growth of the plants you are watering. Some species' natural habitat are swamp lands that are frequently or seasonally inundated. For these orchids, mimicking the wet conditions, at the right time of year, is very important (e.g. Phaius tankervilliae).
Others orchids may come from cool mountainous districts where winter enforces dormancy. Growers of these orchids would need to duplicate a cold winter to obtains good flowering and growth of their plants.
Orchids from dry regions like Western Australia will have a distinct hot dry summer. It is a good idea to check the details of the climate of the orchids you are growing experience in their native growing areas. Some will have damp or rain at different times of the growing cycle, other periods of dryness and dormancy others periods of extended humidity combined often with hot temperatures.
Epiphytic and lithophytic orchids generally require excellent drainage but a fairly constant air moisture.
If you have an understanding of the natural conditions your orchids are adapted to, then you can usually predict with a high degree of success the amount and timing of water applications that they would prefer too.
As a general rule, all orchids in flower or actively growing will require regular watering, however, excess watering will cause root death, increased likelihood of disease occurrence, and possibly rotting of the entire plant. For plants that are adapted to rainforest conditions, high humidity may be very important, so regular fine, mist sprays of water may be needed. For orchids adapted to more arid conditions, less regular, perhaps heavier watering may be appropriate.
As with watering there is great variation in preferred temperatures between different types of orchids. Once again if you have a good idea of the natural conditions to which the orchids you are growing, or wish to grow, are adapted to, then you will have a good idea of what conditions to provide. In general the majority of the epiphytic species are found in sub-tropical and tropical climates, while the majority of terrestrial orchids are found in sub-tropical to temperate climates. These are generalisations, however, and there can be significant variations to this, for example, some tropical zone orchids may
be found at high altitude, where night temperatures can approach zero degrees centigrade.
Many orchids require low temperatures to initiate flowering, so it may be necessary to ensure that night temperatures are 5-10° centigrade cooler than average day temperatures. Many orchids from warmer areas have optimum growing temperatures in the range of 20-30°C., with active growth at temperatures above 15°C. For orchids adapted to cooler climates, growth may begin at temperatures as low as 5-10°C. At temperatures over 30°C. few orchids will thrive. To achieve optimum growth it is important to maintain temperatures that are neither too high nor too low.
Temperature is most readily controlled in a growing structure, such as a greenhouse, or protected shade house, where mechanisms such as heaters, evaporative coolers, misting systems, exhaust fans, adjustable vents can be used. Dampening down the floor of the growing structure will increase the humidity of the air and reduce high temperatures instantly.
On a small scale, protected positions that offer a little more warmth than general surrounding conditions may be used. This may be as simple as placing your plants under a tree to minimise risk of frost exposure, under the eaves of a house (but being careful to ensure adequate watering), or on a protected window sill (inside or outside) as long as too much light isn't received.
Who will benefit from this course?
Any one who is interested in growing orchids will benefit from doing this course. Information provided in this course will help the home gardener who has a passion for growing orchids, and would like to better understand the different varieties and their cultural requirements, through to the commercial producer growing them as cut flowers or supplying the nursery industry.