Orchids will not grow in garden soil. Instead, use Douglas fir bark, mixing 2 parts bark to 1 part perlite. Use fine-grade bark for paphiopedilums, and medium grade for the others. Buy bark where you buy your orchids — at greenhouses and well-stocked garden centers or through mail order orchid catalogs. For best growth and bloom, repot once a year since fir bark breaks down and orchids need a loose, fast-draining medium.
Thorough watering once a week is enough except for large or very small plants. Household humidity that's comfortable to you (40-60 percent) is fine for orchids. (A humidifier will be good for you and your plants!) Or set the pots on pebble-filled trays and add water to the trays to increase humidity around your plants. Make sure the water doesn't reach the top of the pebbles.
Feed orchids twice a month with a balanced organic fertilizer, and give a nitrogen supplement such as fish emulsion at each feeding.
Pests and Diseases
Orchids are remarkably problem-free. Use insecticidal soap to control the most common pests: mealybugs, scale, and spider mites. If a plant shows signs of disease, isolate it, remove affected parts with a sharp, flame-sterilized knife, and watch for recurrences.