Scientific Reasons to Have Indoor Houseplants

Why it's high time to birth some green babies

Adding the outdoors into your indoor living space isn’t just aesthetically pleasing—it’s also hugely beneficial to your health and well-being.

The science on why and how houseplants benefit human health is fascinating. I’ll give you some highlights, then recommend some good plants for beginners, and also give you some tips on how to make it affordable to go green.

What the Science Says About Houseplants: The Cheat Sheet

1. Houseplants improve indoor air quality

2. Potting plants has been shown to reduce stress in young people

3. Houseplants help hospitalized patients recover more quickly

4. Houseplants increase creativity and productivity at the office

5. Houseplants lower older people’s blood pressure

Houseplants Improve Air Quality

This is huge. Many people don’t realize that things like new furniture, office equipment, and conventional perfumes release volatile organic compounds into the air we breathe. Toxic VOCs can impede our breathing, cause asthma, and damage our lungs. Even worse, of course, are the noxious odorless gasses, like radon, that are linked to lung cancer and other health issues.

Plants “breathe” in our carbon dioxide and “breathe” out oxygen. So it makes sense that the more houseplants you have, the more noxious chemicals will potentially be sequestered. These chemicals do no harm to the plants.

A 1989 report by scientists from NASA, “Interior Landscape Plants for Indoor Air Pollution Abatement,” which you can read on-line in PDF form, found that houseplants increase the quality of indoor air, reduce the phenomenon known as “sick building syndrome,” and can even help remove concentrations of indoor air pollutants like cigarette smoke, solvents, and radon.

The 22-page NASA report includes the results of how well different varieties of plants removed chemicals like formaldehyde, benzene, and trichloroethylene during a 24-hour exposure period. Some of the easiest plants to grow indoors—ones that thrive off low light and relative neglect—proved the most effective at sequestering harmful chemicals.

Houseplants Reduce Stress in Young People

In a fascinating set of experiments published in 2015 in the peer-reviewed Journal of Physical Anthropology, a team of Japanese and Korean scientists devised a clever experiment to compare how the human nervous system responds to computer-related activities versus plant-related activities.

They randomly assigned groups of young people to different tasks. Twelve were asked to transplant an indoor plant, another twelve to work on a computer task. After this, the participants switched tasks.

During and after each activity, the scientists evaluated the young men’s psychological and physical health.

The young people transplanting houseplants reported psychological feelings of well being which dovetailed with reduced physiological markers of stress. The researchers found that working with plants even lowered their blood pressure.

“Our results suggest that active interaction with indoor plants can reduce physiological and psychological stress compared with mental work,” the researchers conclude. “This is accomplished through suppression of sympathetic nervous system activity and diastolic blood pressure and promotion of comfortable, soothed, and natural feelings.”

Houseplants Help Hospitalized Patients Recover More Quickly

A randomized clinical trial done by scientists in the Department of Horticulture at Kansas State University, which was published in 2009, found that people recovering from surgery who had live plants in their recovery rooms “had significantly more positive physiologic responses evidenced by lower systolic blood pressure, and lower ratings of pain, anxiety, and fatigue” than patients in the control rooms.

This study included 90 patients recovering from hemorrhoidectomy, which is an evasive surgery to remove hemorrhoids. While hemorrhoidectomy is considered a very effective treatment for hemorrhoids, it is also associated with a high rate of complications, according to the University of California San Francisco.

The patients recovering from hemorrhoidectomy who had plants in their rooms also had more positive feelings about the hospital experience and evaluated their rooms with higher satisfaction when compared with patients in similar rooms with no plants.

“Based on patients' comments, plants brightened up the room environment, reduced stress, and also conveyed positive impressions of hospital employees caring for patients,” the researchers explained.

“Findings of this study confirmed the therapeutic value of plants in the hospital environment as a noninvasive, inexpensive, and effective complementary medicine for surgical patients. Health care professionals and hospital administrators need to consider the use of plants and flowers to enhance healing environments for patients,” they concluded.

If you’ve read Dr. Atul Gawande’s outstanding book, Being Mortal: Medicine and What Matters in the End, you may remember his story about how filling a nursing home that cared for severely depressed and disabled Alzheimer’s patients with green plants, animals, and small children had tremendously positive results.

Having the residents care for plants and animals was the brainchild of a young emergency room doctor named Bill Thomas, who became the director of Chase Memorial Nursing Home in New Berlin, New York when he was just 31 years old. After Thomas introduced literally hundreds of indoor plants (and an outdoor vegetable garden) into the Alzheimer’s patients lives, the need for prescription medications, in particular anti-depressants, was cut in half!

Houseplants Increase Creativity and Productivity

Plants at work also boost creativity and productivity, according to several studies, including one done in 2013 by researchers at the University of Exeter in the United Kingdom and another done in 2015 by a team of Romanian horticulturalists.

The results of the U.K. experiment, which involved 350 office workers, “showed that allowing staff to make design decisions in a workspace enhanced with office plants can increase well-being by 47%, increase creativity by 45% and increase productivity by 38%.”

According to the Romanian scientists: “Results support the evidence of the psychological benefits of ornamental plants on employees and a general preference for plants. The direct impact of these benefits is on well-being and general performance of companies and the incorporation of ornamental plants in the workplace is deemed imperative for the future organizations…”

Houseplants Lower Older People’s Blood Pressure

While some of the results of the research I’ve cited above may seem a bit overblown—and you may have noticed that many of the studies are done in conjunction with agriculturalists and horticulturalists (who already have a clear bias in favor of plants), I think a study done by a team of four scientists in Taipei, Taiwan will convince even the most plant-averse reader that it’s high time to grow some green babies.

This 2020 study, “Houseplant, indoor air pollution, and cardiovascular effects among elderly subjects in Taipei, Taiwan,” was published in the peer-reviewed journal Science of the Total Environment. Unless you’re affiliated with an academic institution, you can’t get it for free on the internet, but the study authors graciously sent me a PDF of their research.

These scientists studied 50 older adults who had houseplants and 50 older adults who did not. They conducted six 24-hour home visits for each of the study’s participants. They found that the adults who lived with houseplants had much less indoor air pollution than those who did not live with houseplants. They also enjoyed better heart health and lower blood pressure.

“The present study supports the hypothesis that exposure to indoor PM2.5 [particulate matter] and TVOCs [total volatile compounds] are associated with increased HR [heart rate] and BP [blood pressure] among elderly subjects in general. The usage of houseplants can benefit IAQ [indoor air quality] and cardiovascular health by indoor PM2.5 and TVOCs removal,” the Taiwanese researchers conclude.

Good Plants for Black Thumbs

The best kept secret is that you don’t need to have a “green thumb” to keep houseplants alive. In fact, there are many houseplants that thrive on a little or even a lot of neglect. Some of these, in particular pothos, can be over-watered or under-watered and do just fine. You forget to open the shades from time to time? You generally ignore them? They’ll usually forgive you and bounce back.

Best of all, the easiest plants to care for also tend to be more affordable. In my experience, it’s the gorgeous most expensive plants that are usually the hardest to keep alive.

Pothos Ivy—is the perfect first choice if you’ve been a plant killer in the past. It’s air-purifying and pretty and it can grow in practically any setting. Your pothos will prefer indirect light (direct sun can scorch its leaves) but it’s not fussy. So if you live in a low-light environment, or want to try a plant in a windowless bathroom, this one’s for you.

This is a trailing plant which is also super easy to propagate. When your pothos starts to get stringy or too long, just give it a haircut and put the cuttings in water. These cuttings will root in a couple of weeks and you can plant them, or gift them to friends or take them to a plant store that offers a free cuttings exchange, like Sun and Soil in Greenville, South Carolina, and exchange them for a different cutting to plant. If you like your pothos, you can geek out on the different varieties. There are something like 15 different varieties, including snow queen pothos, live silver pothos, and golden pothos.

Angel Wing Begonia—You’ll see on-line that begonias are “finicky,” but I don’t think that’s true. They come in all sorts of varieties, they will flower for you in the summer (or not if you keep yours in the shade), and begonias also tolerate forgetful waterers. I love all varieties of begonias. Some have polka dots on their leaves, others have fuzz on their stems. I had a star-leafed begonia that was the most fun and beautiful ever. (I gave her away when we moved. She is sorely missed.) Begonias are also easy to propagate in water. You just have to be patient as they do take awhile to root.

Rubber Tree Plant—Another lovely, forgiving, and beautiful plant. Start with a small one, which won’t cost much. Put it in bright but indirect light. Let it dry out between waterings but don’t desiccate it. A good rule of thumb (though this depends where you live and how humid your home is) is to water your rubber tree—and your other easy-to-care for houseplants—one time per week. Rubber trees are also easy to propagate. Cut the top of it or a side-growing branch that has one or two leaves on it. It will bleed white gunk (aka sap), which may make you feel guilty, but I don’t think the plant is in pain. Put the cutting in water until it roots and then plant it in soil.

I Can’t Buy Anything Right Now, How Can I Afford to Have Houseplants?!

Don’t fret! People who love houseplants love to share. Join the houseplant lovers social media group in your neighborhood or state—you’ll be delighted to see that people are always giving plants away or offering them for very low prices. Also ask your friends for cuttings. And frequent yard sales, where you can easily find plants for just a dollar or two.

Even better: When you walk into a coffee shop or a bar where there are plants growing in abundance, ask the owner if you may take a cutting home. No one I’ve asked has ever said no. In fact, they’re usually grateful to you for giving their plants a trim!

But what about pots? Ceramic plant pots can be expensive, especially at upscale retailers and high end plant stores. Check the local thrift store in your area, as well as the Salvation Army, Goodwill, and Habitat for Humanity Restore, and you’ll find lots of beautiful pots for just a couple bucks.

And what about soil? It’s a little tricker to find affordable organic potting soil, but I just purchased a 50-pound bag for $10 from the farmers market. While it’s easiest to use pre-mixed organic potting soil, you can also save money by making your own with store-bought ingredients or you can try mixing dirt from your own backyard with other ingredients (perlite, vermiculite, coco-coir, and worm castings to lighten and fertilize the soil). It’s hard to get the mixture just right though, so if you’re a novice consider splurging on a bag o’ dirt to get you started.

If you made it this far (did you?), thanks for reading. Now close your computer and go find yourself a plant. But leave a comment first.

Related Articles:
How to Breathe Fresh Air
Save the Original, Organic Humans
It’s Time to Start a New Conversation About Vaccines

About the Author: Jennifer Margulis, Ph.D., is an award-winning science writer and book author. She earned her B.A. from Cornell University, her M.A. from the University of California at Berkeley, and her Ph.D. from Emory. You can join her private email list at her website, www.JenniferMargulis.net, and also read her articles on vaccines, health, and vibrant living at The Epoch Times (behind a paywall). Support independent journalism by becoming a paid subscriber here on Substack, which costs less than the price of a cuppa Joe a month.