Reduce Indoor Air Pollution with Houseplants Part 2: Golden Pothos and Snake Plant

By Chris DurlakIn last month’s newsletter, Peggy Rudberg discussed the peace lily and aloe vera as among the 20 common houseplants studied by NASA for their potential to clean the air in closed environments. Below are two additional low-care plants for you to consider.Golden PothosAlso known as devil’s ivy, golden pothos (Epipremnum aureum) is a widely grown houseplant that tolerates low light levels and even neglect. A member of the Araceae family, it is tropical plant native to the Solomon Islands. Its yellow-tinged foliage give the plant its common name. It has been shown to break down pollutants such as benzene, formaldehyde, xylene, trichlorethene, and torilene.Although golden pothos will grow easily in low light, its variegation is often lost in those conditions. Faster growth and stronger variegation occur in medium to high light. Fertilize monthly in winter months, a bit more often in summer, when the plant is actively growing. It prefers evenly moist soil that dries out slightly between waterings; it does not like to be soggy! When it becomes too dry, its leaves begin to wilt, so it’s obvious when water is needed. To keep the foliage full, periodically prune the long, trailing stems.A note of caution from the ASPCA: Pothos plants can be toxic to pets. Its leaves contain raphides, needle-shaped crystals of calcium oxalate that they cannot digest. If you have a pothos plant, keep it high enough so that pets can’t reach it. It’s always better to be safe than sorry.Snake PlantNative to tropical West Africa, Sansevieria trifasciatais an evergreen perennial of the family Asparagaceae. Its stiff, sword-like leaves grow vertically from a basal rosette, spreading via rhizome. Leaves are dark green with lighter cross-banding and usually range from 28 to 35 inches tall, often shorter when kept indoors. Also known as mother-in-law’s tongue, snake plant is among the toughest of houseplants.S.trifasciatahas demonstrated the ability to absorb toxins, including formaldehyde, trichloroethylene, xylene, toluene, and benzene. As a succulent it is also one of a small percentage of plants that adapted to aridity through a process called cassulacean acid metabolism(CAM). These plants keep their stomata closed during the day to reduce moisture loss; they open them at night to capture carbon dioxide.Snake plant is very forgiving and has few requirements: loose, well-drained soil; indirect but steady light; moderate water and mild fertilizer during the growing season; and monthly watering or less from fall through winter (its one weakness is its susceptibility to root rot). This plant is often recommended for beginners.A Nod to the SkepticsBy Sarah BaldwinThe results of the 1989 NASA study on the air-purifying potential of houseplants have been widely publicized over the years. Environmental scientist Bill Wolverton, who lead the study, went on to publish dozens of technical papers and several trade books on the air- and water-cleaning capacities of houseplants.Still, there are skeptics who claim, fairly enough, that most household environments bear little resemblance to the tightly controlled settings of the NASA study and those of subsequent studies. Some speculate that you would need an enormous number of plants in a home or office environment to obtain anything like the results proclaimed by enthusiasts.Research on the matter continues. Until we know more, it’s prudent not to count on substantial air-cleaning benefits from your houseplants. The EPA and the American Lung Association recommend limiting VOC-releasing materials in the home and ensuring proper ventilation as the best ways to improve indoor air quality.As for our houseplants, let’s thank them for their proven psychological, physiological, and cognitive benefits and for being the resilient, mysterious beings they are, many with origins in forest or desert ecosystems thousands of miles from our homes, now managing to thrive (or at least survive) in modest pots on windowsills and cabinets. That they also add moisture and oxygen to the air around them and reduce pollutants to any degree makes them that much more amazing.