How can I raise the relative humidity indoors for my houseplants?
Many houseplants prefer a relative humidity of 40 to 50 percent. Unfortunately, the humidity level in many homes during the winter months may be only 10 to 20 percent. Humidifiers are an excellent way to increase the relative humidity in the home. Simple cultural practices can also increase the relative humidity around houseplants. Grouping plants together is an easy way to raise the humidity level. The water evaporating from the potting soil, plus water lost through the plant foliage, will increase the relative humidity in the vicinity of the houseplants. Another method is to place houseplants on trays (saucers) filled with pea gravel or pebbles. Add water to the trays, but keep the bottoms of the pots above the water line. The evaporation of water from the trays increases the relative humidity.
Misting houseplants is not an effective way to raise the relative humidity. Plant foliage dries quickly after misting. Misting would have to be done several times a day to be effective. Frequent misting is not practical for most individuals.