National Garden Month

Houseplants Are Good for Your Health

By Charlie Nardozzi and Barbara Richardson

A lavish display of houseplants is not only colorful, it also promotes healthful indoor air.

Press: Open large version of photo for print use.

Did You Know...

To clean the air in a 100- to 150-square-foot room, grow two or three large houseplants (10- to 12-inch-diameter containers). If you use fewer plants, to get full benefit place plants within your personal breathing zone (6 to 8 square feet around you) where you normally sit or lie.

As you walk through the mall, or take a seat in your dentist’s waiting room, you’re likely to share the space with plants such as potted palms, philodendrons, and peace lilies. And you probably have at least a few houseplants on windowsills at home. Whether you notice it or not, their presence is having a positive effect on you, in great part because they actually clean the air you breathe. It’s not just that plants absorb the carbon dioxide we exhale and give us fresh air to breathe in return; they’re also extremely effective at removing environmental toxins, like formaldehyde and benzene, from the atmosphere.

Add to this benefit their subliminal, yet measurable, effect of reducing stress, and the fact that they’re pleasing to look at, and you wonder why plants aren’t more of a priority in schools, hospitals, offices, and other institutional buildings. Fortunately, you can surround yourself with plants in your own home and workspace.

Sick Homes

Research by the Environmental Protection Agency indicates that indoor air can be up to 10 times more polluted than outdoor air. Airborne dust, bacteria, and mold spores can be problematic for many people. Lots of household objects give off chemicals that, in today’s “tight,” energy-efficient structures, can build up to levels that are harmful. For example, plastic grocery bags, paper towels, room deodorizers, carpeting – and as reported in recent news, Hurricane Katrina victims’ FEMA trailers – give off formaldehyde, which can cause eye, nose, and throat irritation; headaches; and allergic reactions. Oils, paints, plastics, rubber, and some detergents release benzene, which can cause skin irritation, headaches, and drowsiness. Appliances, heaters, gas, and oil can give off carbon monoxide that can cause nausea, headaches, and dizziness.

Though we could do the hard work of ridding our houses of every object that emits potentially toxic fumes, it’s a lot easier to clean up the air by bringing in a few leafy green roommates.

Air-Cleaning Houseplants

The ability of houseplants to clean the air has been recognized for decades. In the 1970s and 1980s, NASA research aimed at designing a livable moon base using plants to clean the air yielded results that are applicable right here at home. Some of the best living air purifiers are areca palm (Chrysalidocarpus lutescens), English ivy (Hedera helix), rubber plant (Ficus robusta), Boston fern (Nephrolepis exaltata), schefflera (Brassaia actinophylla), and bamboo palm (Chamaedorea sefritzii).


Thirty-five percent of all U.S households, or 40 million households, grew indoor houseplants in 2006.

They spent an annual average of $34 on houseplants and supplies, and a total of $1.2 billion last year.

Seventeen million households purchased foliage houseplants and 16.2 million purchased flowering houseplants.

The most likely houseplant purchasers are women, married people, college-educated people, people over 45 years old, and households who make more than $75,000 a year.


How do they do it? As part of their normal life processes, plants draw air in through their leaves. The plants themselves break down some pollutants during their normal physiological processes, but soil-dwelling microbes around plant roots do much of the work, too.

What they absorb makes plants great companions, but what they give off is helpful, too. Plants transpire water vapor, making them natural room humidifiers, and even though they grow in soil, they can reduce the amount of interior dust by up to 20 percent, according to research from Virginia Tech. And Dr. B.C. Wolverton, who conducted much of the plant research for NASA mentioned above, discovered that they emit substances that suppress airborne bacteria and mold spores, reducing these hazards by 50 to 60 percent.

Houseplants for Healing

Studies from Texas A&M University report that, in addition to helping us stay well, houseplants can help us heal. After all, stress slows healing, and for hospitals, reducing stress in clinical settings is a priority. Scientists have found that settings containing plants have a measurable influence on recovery even for hospital patients who are acutely stressed. Some achieve benefits after only a few minutes of exposure to plants. Hospital workers benefit too, as they seek plant-filled environments to escape from work stress during the day.

So, whether you need fresh air or an attitude adjustment, indoor houseplants can fit the bill.

Learn how to keep your houseplants happy this winter so they can return the favor: read NGA’s Celebrating the Seasons with Rebecca Kolls.

When You Garden, You Grow!

Every April communities, organizations, and individuals nationwide celebrate gardening during National Garden Month. Gardeners know, and research confirms, that nurturing plants is good for us: attitudes toward health and nutrition improve, kids perform better at school, and community spirit grows. Join the celebration and help to make America a greener, healthier, more livable place!

About National Garden Month

Why Garden?

"Now is the time to plant many of the grasses and wildflowers that are part of the "rainforest" in our area of the planet - the plains and prairies. The time to reaffirm our faith that there will indeed be a future. A time to remind ourselves that each of us has the right and the responsibility to create little spots of health on an ailing planet. A time to do our part, in the hope that our children and our children's children might have a chance to experience the joys of watching the earth wake up from a long winter's rest to flower into a beautiful spring."

-- Bill Neiman, Native American Seed

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