Greenhouse Orchids

The growing of these exotic plants can often become an obsession. Some growers manage to include one or two amongst a collection of other plants and are quite satisfied. Others find the whole group totally absorbing and concentrate on collecting and flowering them alone.

The most important thing to understand is that most orchids are epiphytic and would grow on the branches and trunks of trees. They do not absorb any nourishment from the tree but merely use them as supports. It is lovely if you can rig up a series of dead tree branches for your orchids to grow on. If you have not got the space then small pieces of cork oak bark can be bought for the same purpose. Orchids can be easily attached either on their own or with a pad of Osmunda fibre or sphagnum moss to help them anchor to the branch. Larger orchids can be held by staples and smaller ones by binding of nylon fishing line. Watering of these consists of thoroughly wetting the roots using a hose pipe with a fine nozzle lance attached. Obviously the amount of water given will vary according to weather, temperature and whether the plants are in their resting stage. Watering is different to damping down which is much lighter and done to increase humidity. If you are going to have orchids growing epiphytically there must be somebody on hand to damp down, often four times per day if it is hot and sunny. Alternatively, an automatic misting system must be installed. Given a few years for these orchids to establish you will be rewarded by a fascinating and unusual display.

Even terrestrial orchids would grow in a very light soil of leaf litter. If you are going to grow orchids in pots they must have a special orchid compost which usually consists of orchid grade bark: 4 parts, perlite: 1 part and charcoal: 1 part. This may sound like a peculiar compost but the last thing an orchid wants is for its roots to be surrounded by wet fine compost. After a time the special bark mix will begin to break down into smaller pieces and when this happens the orchid should be repotted.

Even when there is sufficient water in the compost the surface of the bark invariably feels dry to the touch so this cannot be used as an indicator. The best way to test whether you should water or not, is to feel the weight of the pot. If it flies up in the air water is obviously required, however if you can feel a weight in the pot there will be sufficient water inside. The ideal staging is slats of wood over a gravel tray. In this way water drains right away from the bottom of the pot but the plants get the benefit of humidity rising from water in the gravel.

Orchid compost usually contains no fertiliser. Liquid feeding is thus of great importance and I would recommend using a special orchid liquid feed which usually has foliar feeding properties as well. This is essential particularly for orchids growing on trees or cork bark. During the growing season feed should only be applied weekly but every fourth week miss out the feed and rinse the compost through with pure water as this will prevent the build up of salts in the compost which could be harmful to the plants. Some orchids benefit from high potash feeds when they are building themselves up to flower.

Much thought must be given to shading as plants will begin to yellow and produce scorched patches on the leaves if over exposed to light. However, good winter light is necessary for most of them.

If something goes wrong with an orchid it can die a lot quicker than an ordinary plant. Check them over regularly and if there are signs of over-watering, i.e. yellowing and drooping leaves, a spongy feel to the base of the plant and very wet compost, carefully take the plant out of its pot, get rid of all the old stagnant compost and repot it into some new dry mix. Leave for one day before watering in. Thereafter ensure that the pot is very light before watering again. Keep a close look out for red spider mite on thin leaved orchids and for mealy bug, scale and aphids on the rest. Sometimes slugs and even cockroaches can be pests in large collections and are a particular nuisance for eating flower buds just as they are developing.

The orchids you choose to grow will be determined mainly by the minimum winter temperature you can maintain.

23. July 2013 by admin
Categories: Tips and Advice | Comments Off on Greenhouse Orchids


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