Most houseplants grow well with daytime temperatures of 65 degrees to 75 degrees F and night temperatures of 60 degrees to 65 degrees F. Temperatures below 50 degrees F or rapid temperature fluctuations may damage some plants. Keep houseplants away from cold drafts and hot air vents. Also make sure houseplant foliage doesn't touch cold windows. Humidifiers are an excellent way to increase the relative humidity in a single room or throughout the entire home. Simple cultural procedures can also increase the relative humidity around houseplants.
Group plants together.
The water evaporating from the potting soil, plus water lost through the plant foliage or transpiration, will increase the relative humidity in the immediate vicinity of the houseplants. Another method is to place the houseplants on trays or saucers filled with pebbles or gravel and water. The bottoms of the pots should be above the water level. Misting houseplants is not an effective method to raise relative humidity. Misting would have to be done several times daily to appreciably raise the humidity level and is simply not practical.