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One of the most popular orchids grown as houseplants are the Moth Orchids or Phalaenopsis. They make good indoor plants because they can tolerate the drier heat of central heating as well as having extremely long-lasting flowers at any time of year. Around 50 original species come from eastern Asia and The Philippines and grow naturally as epiphytes on trees in the warm, tropical forests.
They do not have bulbs like other orchids but instead grow fleshy leaves, which store food and water with new ones forming from the central crown. They also produce a lot of aerial roots that come over the side of the pot as well as into the bark compost. Their longevity and tolerance together with the thousands of different varieties now available make them ideal orchids for gifts and display
Moth Orchids love the warmth of most modern homes; keep a minimum on winter nights of 18°C (65°F), with a daytime maximum of 30°C (85°F). With central heating many houses have a fairly constant temperature range all year round which suits these orchids well.
Keep shaded from bright, direct summer sun as this can scorch the leaves. Give as much light as possible during the dull winter months
Keep the free-draining bark compost moist all the year round. When watering the plant, remove it from any decorative pot or saucer, pour water through the pot and then let it drain before placing it back in a decorative planter. Never let the pot stand in water. Allow the compost to dry out and the pot to become lighter before watering again. Check the plant once a week and water when required. Avoid water collecting in the crown of the plant as this can cause rot. Add a little orchid fertiliser to the water as directed on average every 2-3 waterings. Spray the aerial roots regularly with water, trim when they have died off. A Phalaenopsis with many aerial roots is a healthy, happy plant.
Re-pot your Phalaenopsis when it is climbing out of its pot. Choose a time when its flowering has finished and the roots are actively growing. Cut the old stem right back to the base and if still in flower, the blooms can be placed in water. Remove the plant from its pot and shake off all the old bark compost. If it has been several years since it was last potted then the compost may have started to break down. Using clean, sharp secateurs or scissors, trim back the roots to a length of about 10cm minimum. Healthy roots should be white or green and plump. Over-watered roots are brown and shrivelled. Take this opportunity to completely remove any dead leaves and roots. Position the plant in a clean pot, slightly bigger if necessary and hold in place, centrally with one hand, whilst filling up with fresh bark compost with the other. They grow well in clear pots but these are not essential. Choose any container that has plenty of drainage holes. Making sure the bark is pressed down firmly to anchor the plant, top it up to just below the rim of the pot. Use the clear pot to your advantage, keep an eye on the roots and you will see if they are keeping healthy.
Along the length of the main stem there are many eyes or nodes. Before all the flowers have died and the sap is still rising, cut the stem right off above the highest node. If it is not cut until the flowers have dropped then the stem may start to die back.
The node will then soon start to produce a side branch with more flower buds. When these have all flowered, repeat by cutting above the next node down the main stem and so on. As long as the plant looks healthy you can continue to encourage it to re-flower many times. When the base of the stem is reached or it fails to re-bloom for you, then cut off at the base. The plant will probably then make a new leaf before its next stem is made.
Culture information taken from the Growers and Buyers Guide to Orchids in the UK – 2013 (Golden Guide).
Photographs supplied by S. Pask unless stated.