Many houseplants such as Calathea, Ferns, Caladium, African Violets, and Prayer Plants prefer high humidity. The 40 to 50 percent humidity level some houseplants like is rarely found in our homes and offices. During winter months, the humidity may be as low as 10-20%. Misting houseplants is not the solution to this problem. Misting does not increase the humidity in the air; it just wets the leaves so the plant doesn’t lose as much water. The down side is that leaves that are constantly wet fall prey to bacterial and fungus infections that often destroy the entire plant.
If you want to increase the humidity in a room just install a humidifier; a small one for just one room a large one connected to your heating system for the entire house. There are also simple little things you can do to increase the relative humidity around houseplants. Place your plants on wet pebble trays. Just fill a tray with gravel and water and set your plant in it. Be sure the plant is sitting on the gravel and above the water line. You never want a houseplant to be sitting in water all of the time. You can also just group your plants together. As the plants transpire, give off water through their leaves, the humidity around them increases causing a mini greenhouse effect.