Keep orchids of all types in appropriate foundations. Orchids need loose, airy foundations such as peat moss, gravel, fir chips, fern matter or bark. They suffocate and rot in traditional soil.
Put orchids in brightly lit indoor rooms. The plants thrive with bright artificial light during the day and grow well with standard overhead lighting. Low-light orchids like phalaenopsis do better in artificial light than in natural sunlight, which may burn them. Keep the lights on for eight to 10 hours a day.
Fill shallow pans with water and gravel and place the orchid pots in the water. Heat causes evaporation from the pans to produce natural humidity. Indoor orchids need 50 to 80 percent humidity.
Water indoor orchids when their potting medium dries. Start with a schedule of 2 inches of water every seven to 10 days. Don't over-water the orchids, as they prefer dry environments to wet ones.
Feed orchids with water-soluble 20-20-20 fertilizer every other week. Mix the fertilizer with water at one-quarter the recommended rate and apply this mixture as a standard watering. Don't get water or fertilizer on the foliage.
Maintain controlled temperatures in the room. Phalaenopsis orchids do best in daytime temperatures of 72 to 78 degrees Fahrenheit, with nighttime temperatures over 60 degrees. Cool-temperature orchids like cymbidiums do best with cooler nighttime temperatures of 45 to 50 degrees Fahrenheit. Intermediate orchids like oncidiums and dendrobiums fall into the middle, with temperatures of at least 55 to 60 degrees. Use heating vents to warm the room and open windows to cool as necessary.