Humidity for plants refers to the amount of water vapor in the air that is available for plants and is not easily controlled. The good news is that although many houseplants, like the calathea or pilea prefer high humidity (50-70%), most, like a peperomia or kalanchoe manage to do quite well in the 20-60% humidity found in our homes and offices. However, it’s always a good idea to find out how much humidity a specific plant needs; for example, thin leaved, delicate plants usually require more humidity than thick leaved succulent plants.
How to Increase Humidity for Plants
Low humidity is often a problem during the winter when the heat is on and in the summer when the air conditioning is running. When the air is too dry, houseplants develop brown leaf tips, leaves curl, wither, and may eventually fall off. There are several ways to increase the humidity in a room.
Place a small room humidifier in the room near your plants.
Group plants together and create a mini greenhouse effect: All plants put water from their leaves into the air in the form of water vapor. This process is called transpiration. As the water vapor enters the air near the plants, it increases the humidity around the plants. The more plants you group together, the more water vapor in the air, and the greater the humidity.
Place a plant on a wet pebble tray. When you do this, be sure the water stays below the bottom of the pot and the plant sits on pebbles and not directly in the water. The pebbles should be pea size and the tray should be about an inch deep and twice as wide as the bottom of the plant pot. As the water evaporates, the humidity in the air increases.
Misting Plants: I do not recommend misting plants. Leaves that are constantly wet tend to develop bacterial and fungal diseases which are more serious problems than lack of humidity. Also, it’s not very efficient since the mist dissipates so quickly it rarely increase the humidity for an adequate amount of time.
Place your plants in a bathroom since this is the usually the most humid room in the house.