Disclaimer: The growing guides are provided only as a starting basis to cultivation. Local conditions in your area may require modification to these suggestions. Bankstown Orchid Society Inc. will not be responsible for the results of your cultivation practices.
Phalaenopsis, the Moth Orchid, and its alliance, are one of the best orchids for growing in the home, and are also a favourite with glasshouse growers.
Temperatures: Should usually be above 16°C at night with no draught present, and range between 24-29°C as these plants do not have a resting period. Although higher temperatures force faster growth, higher humidity and air movement must accompany the higher temperatures, the recommended maximum being 35°C. Night temperatures between 16 -18°C are desirable for several weeks in autumn, in order to initiate flower spikes. As they experience little seasonal change in their natural habitat, fluctuating temperatures can cause the buds to drop on plants with buds ready to open. An ordinary thermometer placed around the place should provide a guide.
Light: They grow easily in a bright window spot, with little or no sun. A north facing window is ideal in the home; shaded west windows are acceptable. Artificial lighting is excellent. Usually four fluorescent tubes in one fixture are placed 150 - 300mm over the leaves, 12 -16 hours a day, following natural day length.
Water: As they have no major water-storage organs other than their leaves, they must never completely dry out. Plants should be thoroughly watered and not watered again until nearly dry through the pot. (In the home, with good ventilation, twice a week, in summer will suffice; in winter, once every five days.) However, in the heat of summer and when the humidity is low, watering may be carried out every other day. Watering should be done only in the morning, avoiding the crown if possible, so that the leaves, and crown, are dry by nightfall. This is to prevent rot as Phalaenopsis are prone to if left wet overnight.
Humidity: The recommended humidity being between 60% and 80%. In the home, stand the plants over trays of gravel, partially filled with water, so that the pots never sit in water, but above it. Mist the plants often on dry days, or during dry weather. Grouping plants together help raises the humidity. During humid days, ensure that the humid air (not draught) is constantly moving to prevent fungal or bacterial disease. A small fan, blowing away from the plants may help. Again, leaves should be dry as soon as possible, always by nightfall.
Fertilizer: Should be applied on a regular basis, especially if the weather is warm and when the plants are most often growing faster. A weak feed once a week is adequate. Fertilizers not high in nitrogen are ideal, such as Peters Excel Hi-K and Campbell's. This can be applied with normal watering. For flowering, a high phosphorus fertilizer like Campbell's Yellow may be applied to promote flowering. Fertilizer should be applied with tepid water once a month during the cooler season.
Potting: This is best done in the spring or after flowering. Cutting back of spikes after flowering should be done on 'die-backs'. This will encourage further flowering spikes from the remaining 'eyes' on the old flowering spike. Phalaenopsis plants must be potted in a well-drain mix, such as bark, washed coir chunks, perlite, sphagnum moss, or a combination of these. Potting is usually done every 1-3 years. Mature plants can grow in the same pot until the potting medium starts to decompose, usually in two years. Root rot occurs if plants are left in a soggy medium. Seedlings usually grow fast enough to need repotting yearly, and should be repotted in a finer grade medium. Mature plants are potted in medium-grade medium. When mature, a plant may stay in the same pot for many years, but must have the medium changed. To repot, remove the old medium from the roots, trim soft, rotted roots, and spread the remaining roots over a handful of medium in the bottom of a new pot. Fill the rest of the pot with medium, working it through the roots, so that the bottom leaf is above the medium. Keep the plant shaded and humid, but drier in the pot, for several weeks to promote new root growth. A vitamin B-I solution may be helpful in establishing plants.
Pests usually found in Phalaenopsis are mealy bugs. Periodic spraying with Eco-oil will control their numbers.