Orchids as house plantsDecember 24, 2000
There are a few general guidelines for growing orchids in the house. Good lighting is essential. They like an east or west facing window, but shaded from direct sunlight. Orchids need 10-15 hours of light each day. Supplemental light may be needed in the winter. Plants must be protected from unfiltered sunshine. Occasionally turn the pot, and move the tray away from the window on cold and frosty nights.
Good ventilation is required year round as orchids do not tolerate hot and stuffy conditions. Day temperatures should be about 70F in summer and 60F in winter. Cool nights are important and there should be a 10F drop but avoid cold draughts which can be fatal to orchids.
Water orchids when the growing mix feels dry to the touch, then soak thoroughly using soft, tepid water. Since orchids are grown in a fast-draining mix, you need to allow time for the water to be absorbed, then water again, covering the entire soil surface. Allow excess water to drain away. An orchid mix should not be kept constantly wet, nor should it be allowed to dry out completely.
Orchids thrive in a humid environment. To increase the humidity, place the plants on a tray of small damp pebbles. Keep the pebbles moist by filling the tray with water up to the bottom layer of pebbles. The pot should not be sitting in water, only on top of the pebbles. The water will evaporate from the pebbles and moisten the air around the plant. Misting the leaves will also increase the humidity. Mist in the morning so the moisture will evaporate by evening. Never directly spray the plant, but spray around it so that a fine mist settles on the foliage.
Orchids like to be pot bound. Repotting and division may only be necessary every few years. When repotting, use a special Orchid Compost.
Fertilizer is necessary for healthy growth. If you are using a mix that includes fir bark chips, the fertilizer should be a water-soluble 30-10-10. Apply the fertilizer as recommended on the label once a month or half strength every 2 weeks. Fertilizing every 2 weeks with a half strength fertilizer will provide a more continuous nutrient supply. Orchids grown in a tree-fern-fiber-based mix should be fertilized with a 20-20-20 water-soluble fertilizer every month at full strength, or every 2 weeks at half strength.
Many orchids do require a resting period. This is usually in late autumn or early winter. During this resting period, they may loose their leaves, leaving only the pseudobulbs. That's ok since new growth will come from the pseudobulbs. During this stage, the plant will need very little watering, only water if the potting soil is completely dried out.
Occasionally things can go wrong even if you follow the growing instructions. Brown spots can develop on the leaves. If the spots are hard and dry, the plant has been scorched by the sun. Shade will be needed, but there is no need to remove the spots. If the spots are soft, it is caused by a fungal disease. The affected parts should be removed.
The most common reason for horizontal or drooping growth is lack of light, orchids do need good lighting. If the growth is limp, but the lighting is good, then it is likely due to incorrect watering.
Mildew may develop on the leaves if the plant is misted under cool conditions and the water on the leaves did not evaporate fast enough.
Orchids benefit from time spent outside during the summer. Sometimes outdoor pests can attack. If whitish cottony tufts are seen on the leaves and pseudobulbs, it is caused by mealybugs. A severe attack will yellow the leaves and weaken the plant. Remove them with soft Q-tips moistened with rubbing alcohol.
Red spider mites or thrips will give a yellowish or brownish mottling to the leaves. The leaves will die prematurely.
If there are small yellowish leaves and pseudobulbs as well as few or no flowers, fertilizer is needed or the soil mix is too wet. Repot in new soil mix and water carefully.
If the flower buds fail to develop properly, usually withering or falling early, it is too cold or too hot and dry. Make sure adjustments are make.
Do not be afraid to try growing an orchid as a house plant. Orchids will grow in the basement, sun porch or living room if they are given the proper light, temperature, and humidity.