Successfully transition houseplants indoors for winter

(Photo courtesy of Gardener’s Supply Company) Using a combination of artificial and natural light helps plants better tolerate the less-than-ideal indoor growing environment.

I have a recent fascination with houseplants.

Within the last few months, I have acquired more than 10 houseplants, a lemon tree, a lime tree and an herb garden for my windowsill. It has been a lot of watering and transplanting, but I found that being a plant mama brings me happiness.

To back up my new obsession, I decided to look at some studies on the effect of houseplants on health. And now, I am going to share what I learned with you.

If you go to any greenhouse or garden center, you will likely see signs for air purifying plants. In 1989, NASA did a study on the effect of over a dozen common houseplants on air quality. They placed plants in a sealed chamber with high concentrations of common indoor toxins like benzene, trichloroethylene (TCE) and formaldehyde. All of the plants removed at least one of the toxins NASA tested from the air, although some plants were more effective than others at removing various toxins.

Examples of plants from the study that helped purify the air are gerbera daisies, spider plants, peace lilies, areca palms, English ivy, pothos, bamboo palms, Chinese evergreens, various philodendrons and dracaenas, aloe vera and snake plants. Some claim that this study does not apply to large open spaces like a home since the study was done in sealed chambers. It’s up to you to research and decide.

Regardless of air purification, having houseplants around can lower your stress and boost your mood. Studies have consistently found that plants, gardens and nature in general increase feelings of peacefulness and calmness, reduce negative emotions and decrease stress.

Researchers have devised interesting ways to measure physiological and psychological changes caused by exposure to plants. In one study, researchers randomly divided 120 stressed people into two groups. The first group was assigned to look at videotapes showing human-made settings like rooms, buildings, and towns. The second group was assigned to look at videos featuring natural settings like greenery, plants, and flowers.

The researchers found that overall, the group observing natural scenes had improved blood pressure, heart activity, muscle tension and brain electrical activity compared to those watching the man-made scenes. The people who watched the nature videos reported higher levels of positive feelings and lower levels of fear and anger than people watching the man-made environment videos. And these effects are just from watching videos of plants rather than actually being around them!

In another interesting study, researchers had participants view potted plants with flowers, potted plants without flowers, empty pots or a cylinder. They measured brain wave activities while participants viewed the objects. The researchers found participants were most relaxed when they observed plants with flowers and least relaxed when they looked at pots without plants. In a follow-up study, the researchers looked at participants’ brainwaves while sitting outdoors viewing a hedge of greenery, a concrete fence or a structure composed of part greenery and part concrete. Brain wave activity showed that the greenery brought relaxation while the concrete produced stress. (Nakamura and Fijii 1990, 1992)

Since my love for plants started, I have been told “crazy plant lady is the new crazy cat lady.” But I think the research is on my side. If you want to see some serious indoor planting, check out the Facebook group Houseplant Hobbyist. Happy planting!

Dr. Sarah Hall is an assistant professor of public and community health at Utah Valley University.

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