Humidity for Houseplants

In Washington state, low temperatures and low humidity go hand-in-hand because cold air cannot hold water vapor. A hygrometer can measure temperature and relative humidity. Normal household humidity is sufficient for most houseplants, ideally 40-50%. However, there’s some tropical varieties that require increased humidity such as air plants, calathea, ferns, and marantas. Dry environments quickly wick away moisture from the leaves turning edges brown and crispy.

Try these simple ways to increase humidity.



Did you know plants exhale? Plants release water vapor into the air in a process called transpiration. Geek out on the whole cycle here


pebble tray

Add water to the level of the pebbles, but not above. Evaporation increases humidity. Photo credit Jen D.



The shop humidifier is an ultrasonic cool type which is very quiet and actually sounds like a trickling fountain. I fill it daily and occasionally add a couple drops of eucalyptus oil. Because it doesn’t have a filter, it requires weekly cleaning.


warm shower

Place plants in shower and use a protective tray or towel underneath to prevent dirt from going down drain. If space allows, temporarily relocate plants to bathrooms which are naturally higher in humidity during dry winter months. Photo credit Pam G.



Spritzing stems where they meet the soil can increase humidity. Spritzing new leaves as they unfurl can prevent deformities due to dryness. However, I have experienced leaf spot, a fungus, requiring cutting the leaf off to prevent spread.



Creating a closed environment can create an ecosystem in a beautiful desktop garden.

Jeanne Serrano