Most homes, offices, and malls are very dry and are not conducive for good plant growth. Most interior plants do best under high humidity (60 to 90%). There are several ways to raise the humidity when it is too low. One way is to place small gravel in a shallow pan or saucer and fill with water almost to the top of the gravel. Place your plants in the gravel-filled saucers. The water will evaporate from the surface of the gravel, thereby raising the relative humidity around the plants above. When placing the plants on the gravel, be sure the bot tom of the pot is not below the surface of the water. If the plant sits in water, it may become overwatered, lose its roots, and die.
Another way to raise the humidity around your plants is to group them close together. Since each leaf loses moisture through the leaf pores (stomata), the moisture lost by one plant helps raise the humidity around another and vice versa.
Wetting the foliage with a fine mist of water will also help raise the humidity around your plants. However, the effects on the humidity are very short and repeated mistings will be required. Take care not to mist the plants late in the evening as the foliage may stay wet all night and increase the chances of disease. Over-misting during the day may also increase the chance of disease. Misting the plant is the most inefficient methods of raising the humidity around plants for an extended period of time.
Another alternative to increasing the humidity is to install a room humidifier. This works well for larger areas. For small areas, the old-time room vaporizer that mom used when you had a cold or the croup can be used. Just leave off the Vick's salve and set the vaporizer for cool moisture.