Orchid Articles: Green House Construction   

By Col in Silver

 

Having been inspired to grow orchids, your collection is certain to increase at a rapid rate and you will need somewhere to house them. Constructing a greenhouse or shade house is normally the most sensible option for a variety of reasons, not least of which is the convenience of having all your plants in one area and not spread around the garden. This makes watering and fertilising more efficient. Having all your plants in close proximity also enables you to quickly and easily inspect them for disease or uninvited `noonoos', and makes effective treatment less troublesome.

Greenhouses in , being in the southern hemisphere, need to face north or as close to it as possible. This will allow maximum light for the longest period as the sun travels from east to west. Do not build your structure under or close to trees that are going to obstruct sunlight.

Before starting construction, consider carefully what area you wish to allocate to your orchids, remembering that your collection will almost certainly continue to increase. Decide well in advance exactly which genera you are going to concentrate on, as this will determine the amount of shade that you will need to provide. Small areas can easily be created later for compulsive introductions of new genera you wish to try your hand at.

You will need to refer to previous articles in this series to determine shade percentages for each genus, but as a general rule 40% to 60% shade for Cattleyas, Oncidiums and Dendrobiums is considered adequate and 70% to 80% for Paphiopedilums and Phalaenopsis. Some Vandas and Cymbidiums will grow in full sun but prefer ±30% shade.

Construct benching at a sensible height and preferably with mesh or slatted tops rather than solid, to allow for air circulation around the plants. It is advisable to have at least part of the roof constructed from translucent fibreglass or polycarbonate sheets to prevent rain damage to flowers and plants. Adequate air move­ment is essential in a greenhouse; if solid walls are preferred then fans must be installed to keep air buoyant. Ensure that a water point is in close proximity to your greenhouse as frequent watering is essential, especially in summer. Whether you need to provide additional humidity will be determined by your geographical location within .

Joining an orchid society will be of enormous benefit when you begin considering constructing your greenhouse or shade house, as other growers in your area will provide a wealth of information regarding local conditions.