Orchids that grow in the ground are known as terrestrial. Many orchids, however, naturally grow in trees and are known as epiphytic. Most of the orchids people like to grow in pots at home are epiphytic. They are splendid plants that produce remarkably beautiful flowers. Understanding a little about how these orchids live in nature will make it easier to grow epiphytic orchids in the home.
Orchids used to be very expensive and difficult to obtain since propagation was complicated and time-consuming. New methods called meri-cloning have made plants easier to propagate so it is easier to buy these glamorous plants at affordable prices. But they still need to be cared for properly if you want your orchids to thrive and show off their fantastic blooms.
Small bark chips make a good potting medium for epiphytic orchids. Epiphytic orchids naturally grow high above the ground in the crotches of tree branches where composting organics collect. Their root systems function as much to attach them to the branches as for growth and feeding. This information is useful because it tells you something about how to care for the roots of your epiphytic orchid. You will want to grow it in a porous container like clay or wood with big drainage holes so water drains through quickly and there is plenty of air circulation around the roots - just like in nature. You will also want to use a very loose, jumbled rooting medium that will drain faster than soil. You can buy orchid mix made just for this purpose. Epiphytic orchid roots wander in and over their containers with good air circulation. More orchids are lost to over-watering than for any other reason. That's why watering needs to be done regularly with impeccable drainage.
Epiphytic orchids also need good light. They will burn in full sun since they have evolved under the dappled shadows of the upper foliage of overhead branches. So give them similar light exposure if you want the best chance for success.
Some popular epiphytic orchids that grow well in pots are Phalaenopsis, Oncidium, Cattleya, Dendrobium, Vanda, Odontoglossum, Brassia, Paphiopedilum, Miltonia and Epidendrum. There are many more and even more crossed varieties. Some are more demanding than others. All prefer high humidity.
These are just some of basics behind growing epiphytic orchids successfully. Let nature be your guide. There is a lot more to growing orchids such as allowing them rest periods, pruning, feeding and re-potting. Much information depends on the type of orchid you are growing. Check out the Internet and any of the wonderful books available that detail the needs of different orchid species.