Why Is Humidity Important For Bonsai?
Although indoor bonsai slow their growth in winter and do not need as much water, they still do require sufficient humidity. Humidity helps to reduce water loss through the processes of transpiration. Transpiration will have a negative effect on your bonsai's ability to retain water and remain healthy.
How Can Humidity Be Improved?
The sometimes dry climate of a home or apartment can be altered to benefit your bonsai tree. Placing your bonsai on a "humidity tray" filled with decorative pebbles, that should be kept wet at all times, will help increase humidity levels. Another solution is regular misting. Misting is the most common humidifying method. It has the additional benefit of removing dust from your bonsai, which blocks sunlight and interferes with the exchange of oxygen and carbon dioxide. Be sure to mist using room temperature water to avoid shock.
What Else Is Helpful To Prevent Dry Conditions?
Keep your indoor bonsai trees away from breezy doors, windows and heating sources, such as vents, radiators, and fireplaces; to avoid quickly drying them out. While more sunlight is desirable, it may dry out your bonsai. So, maintaining a watering schedule during winter is just as important as during summer.