Misinformation reigns in the world of houseplant care. It's time to bust some myths! Here are some pieces of particularly bad plant advice that I'd like to see retired.
1. “This plant will clean the air inside your home.”
I’ll be the first to admit, I’m guilty of telling this to customers when I worked at a nursery! But sometimes it’s hard to break the truth to someone when they ask you specifically for plants that do this, and you need to make a sale. But decades of research published in the Journal of Exposure Science & Environmental Epidemiology last year gave us a definitive answer: the rate at which houseplants clean the air is so slow that it’s pretty much negligible. Even if you had had a potted plant for every square foot in your house, the natural air ventilation from opening and closing doors would still be cleaning the air more.
2. “You should mist the leaves of your plant to create humidity.”
This one is a bit of a mixed bag. In theory it makes sense that if houseplants are from tropical regions they would extra moisture. But moisture in the air and water droplets on leaves do different things. Droplets left to sit on a leaf surface can invite bacterial infections, fungal infections, or malformed leaf growth. Of course there are some exceptions, like certain carnivorous plants or bromeliads that like a boggy environment. But most houseplants are successful in homes because they are perfectly adaptable to the home environment, and don’t need extra humidity. They do, however, appreciate being wiped down since dust buildup on leaves can inhibit processes like photosynthesis and transpiration that keep the plant alive. So spray your leaves from time to time, but be sure to wipe off the excess water off after.
3. “Use a pebble tray to create humidity.”
I often see this recommended for plants like calatheas or ferns. If you have a particularly needy plant, or an especially drafty environment with a fan, air conditioner, or heater constantly running then it’s true you may want to raise your humidity. The concept of a pebble tray is simple: you place your plant on a shallow dish with a bed of pebbles in some water, and the water will evaporate to create ambient humidity around the plant. But you can easily debunk this one yourself by getting a digital hygrometer––about $6 at your local reptile shop––and placing it near your pebble tray to see that the humidity does not increase. Leave the water in the tray for a few days and you may notice mold, algae, fungus gnats, and/or a mildewy smell. To raise your humidity without inviting these problems, I recommend getting a good humidifier and pairing it with a fan for constant air circulation while it is running.
Have you fallen for these myths before? Or have another one you want debunked? Share about it in the comments!
1. “Potted plants do not improve indoor air quality: a review and analysis of reported VOC removal efficiencies,” Journal of Exposure Science & Environmental Epidemiology, November 2019, https://www.nature.com/articles/s41370-019-0175-9.