House Plants Can Help

     One effective air filter you don't have to send away for is the house plant. When the National Aeronautics and Space Administration (NASA) discovered in 1973 that Skylab's tightly sealed air contained over a hundred toxic chemicals, the agency began a search for solutions. Learning that Russian scientists were experimenting with live plants as air purifiers, NASA hired research scientists to explore that possibility. The researchers found that all house plants share the ability to remove contaminants from the air by pulling them into their leaves. 

     The toxins migrate to the roots and into the soil, where they decompose. Trichlorethylene, formaldehyde and benzene, three common pollutants, were treated in sealed growth chambers by common plants such as the peace lily, lady palm and corn plant, any of which could clean the air in a small (10'-by-10') room. As the study discovered, the more house plants you have in a home or office, the more pure the air becomes. Other research has shown that the popular spider plant consumes tobacco smoke and that philodendrons and aloe vera are effective air purifiers. 

    To help your plant collection improve the quality of indoor air, place a layer of activated carbon at the bottom of each pot before adding soil; place a drop or two of grapefruit seed extract or tea tree oil or a tablespoon of topical hydrogen peroxide in drainage dishes every week before watering to prevent the growth of mold and bacteria in standing water; keep air circulating around the plants with a low speed fan; position plants at different heights; use a variety of plants; position shade-loving plants in areas that receive little or no natural light and place sun-loving plants near windows; use at least one plant for every 100 square feet of floor space (two is better) in rooms of average height and increase the number of plants for rooms with high ceilings, in areas in which cigarettes are smoked or in homes near busy highways. Where necessary, supplement natural light with plant lights. Feed and water your green friends and they will repay you handsomely.
    While mold can be a problem in greenhouses and other humid, plant-filled spaces, carefully tended house plants don't have to promote the growth of mold. The most common problem of this nature is over-watered plants that stand on carpeting. Any carpet that becomes saturated and prevented from drying out will develop serious mold and mildew infestation. Anyone concerned about potential pathogens in the potting soil can prevent its contact with the air by spreading several inches of aquarium gravel over the top of the soil, or you can spray the surface with a dilute solution of grapefruit seed extract and water. For a wealth of information on indoor gardening, see your local library and visit nurseries and plant stores.