Orchid Care: Paphiopedilum
These old world relatives of temperate North American lady’s slipper orchids are one of the best for home growing. The foliage is compact and more attractive than most orchids and the blooms are especially long lasting. Although there are several general types of paphiopedilums, or "paphs," requiring slightly different cultures, all should do well with the following care instructions.
TEMPERATURE Mature plants can handle nights of 50º to 60º F and days of 70º to 85º F. Try to keep a 15 to 20º difference between night and day. Seedlings need 5 to 10º higher than mature plants. In general, a plant with green leaves can be grown in somewhat cooler conditions, while plants with moled leaves prefer slightly warmer conditions.
LIGHT No direct sun. Provide low to medium to some bright light in an east, shaded west or south window. Under lights, 40-watt fluorescent bulbs (4) and 40-watt incandescent bulbs (2) over the plants. Watch for dark green limp foliage (indicating too little light). In the greenhouse, paphs should receive 70 to 85 percent shade.
WATER Mature plants should never dry out between waterings. Seedlings require constant attention to their moisture needs. Do not allow water to drip down into the center of the plant. Water standing in leaves causes rot.
HUMIDITY Paphs require 60 to 70 percent humidity. Place plants (in pots) above trays of moist pebbles. In the greenhouse use a humidifier if conditions are too dry.
POTTING & FERTILIZER Paphs should not remain in stale media; they respond well to repoing. Straight fir bark is excellent. Finely chopped (1/8 to 1/4 inch) is preferable to larger chunks. With fir bark, use a high nitrogen fertilizer (30-10-20 or 30-10-10) at half strength. Fertilize every other watering. Plants grown in professional mixes or commercial mixes of peat, sponge rock or perlite and bark should receive 20-20-20 at half strength. Consistency is the key and too little is more desirable than too much. Repot every one to two years at any time except except when plant is in bud or bloom. Avoid placing your orchid in too large a pot.