Whether you're an orchid expert or a novice, the more knowledge you have the more successful your orchid growing efforts will be. The first time your orchid plant sends up a flower spike, you will undoubtedly feel a sense of accomplishment because these plants require the correct temperature, humidity, light and other environmental conditions. Many orchids also require special fertiliser to encourage blooming. When you take care of all their needs, you will be rewarded with a blossom. But trimming spent flowers or spikes is the next step: it's important to perform this task correctly.
Determine the type of orchid you are growing, because different varieties have different types of flowers and flower spikes that you should prune in a specific way to benefit your plant.
Cut flower stalks of Dendrobium, Cattleya, Oncidium and other common species of orchids to within 1 inch of their growth point at the base of the plant when they become yellow and all flowers have died. Sterilise sharp garden snips, clippers or a one-sided razor blade by wiping the blades with a rag moistened with isopropyl alcohol. Cut flower stalks straight, not at an angle. Cutting stalks in this manner will prevent the stalk from producing more flowers. Sterilising your cutting tool will prevent the introduction of any disease.
Trim the tip of Phalaenopsis flower stalks that remain green and fleshy and that have one or more nodes below the area where you will cut. Cut at least ¼ inch above the uppermost node. This practice can help the plant to produce additional flower stalks below your cut but is not recommended for Dendrobium orchids.
Cut all dead and damaged leaves and stems when your orchid enters its winter dormant season or when they detract from the plant's appearance at any time of year.
Snip off spent flowers while a flower stalk is blooming to encourage the plant's production of additional flower buds.
Trim unhealthy roots by taking the orchid from its pot and examining the roots: healthy roots are springy with a pale coating, while unhealthy roots are soft and dark coloured. It benefits the plant when you prune unhealthy roots. Then repot the orchid in fresh bark growing medium and a clean pot.