Nephrolepis exaltata, also known as Boston fern, is an evergreen fern with beautiful light green fronds that, when the plant grows indoors, are small, around 20-40 centimeters in length. The fronds fall elegantly to form a beautiful natural cascade and that is why the fern is definitely a splendid ornamental house plant. But placing a beautiful fern in the living room or office is not only an aesthetic choice, it is in fact even a healthy one! In fact, the Boston fern is one of the plants studied by the American scientist B.C. Wolverton in the 1980s at the request of NASA. In fact, NASA wanted to understand how plants could improve the microclimate in space stations by removing toxic substances from the air. Wolverton compiled a list of about fifty plants that are particularly effective at removing toxic and carcinogenic substances from the air such as formaldehyde, a carcinogenic substance produced during combustion processes, exhaust gases, industrial fumes, but also released from new furniture due to particular glues and resins used, and xylene, a substance irritating to the lungs, toxic to the central nervous system and emitted by printers, but also by paints and glues. Among all the studies plants, the Boston fern certainly stands out. But let's see what exactly the American scientist says in his work, which can also be consulted online published in The Journal of the Mississippi Academy of Sciences (Wolverton et al, 1993).
Boston fern and its anti-pollution properties
As Wolverton himself states, among all the plants tested, the Boston fern was found to be the most effective at removing formaldehyde, eliminating it at the rate of 1863 micrograms per hour, immediately followed by chrysanthemum, 1450 micrograms per hour, and the phoenix roebelenii, or dwarf date palm, 1385 micrograms per hour. In order to better understand the action of the fern, in 1988 the EPA, the United States Agency for the Protection of the Environment, estimated that a new office, recently built, with a size of 9 square meters and a ceiling with a 2.5 meter height, can contain up to 3900 micrograms of formaldehyde. This estimate is in line with other measurements made in subsequent years also by other environmental protection agencies, which have found formaldehyde values ??in closed environments such as offices and bedrooms between 50 and 170 micrograms per cubic meter (Kaden et al, WHO Guidelines for indoor air quality, 2010). In this case, two ferns would be enough to remove all the formaldehyde. But Boston fern also helps remove xylene. Also in this case, estimating a contamination level of 493 micrograms per room, two ferns would be sufficient to remove the toxic substance from the air. Finally, Wolverton, in his study, also observed a peculiarity regarding the Boston fern, namely that the fern's ability to remove formaldehyde from the environment increases with the time the plant is exposed to the substance.
Boston fern, cultivation
As far as cultivation is concerned, the Boston fern thrives well in bright environments, but away from direct sunlight, especially in summer. The plant cannot stand the cold and the minimum tolerated temperature is around 7 degrees, which however is not a temperature that is reached in an apartment. Do not exceed with the watering, the soil should in fact be kept only slightly humid. In summer it is best to spray on the leaves a little water.