In addition to its esthetic value, a vertical garden (or green wall) has the ability to improve the environment within buildings by reducing the noise and temperature changes; besides, the plants it holds absorb atmospheric pollutants and may turn into bird’s perching and feeding places.

These gardens and green rooftops are called urban naturation systems and its installation objective is to improve the appearance of the constructions and bring to them the “green” idea, related with environmental sustainability.

Due to the importance these green areas have for the environmental balance, the World Health Organization recommends from 9 m² to 16 m² of them per resident in metropolis; despite this, Mexico City has an average of 5.3 m².

“This deficiency has implications for the welfare of individuals, since the interaction with those spaces reduces anxiety and depression”, affirmed Saraí Montes, researcher at the Institute of Ecology (IE, Instituto de Ecología) of the National Autonomous University of Mexico (UNAM, Universidad Nacional Autónoma de México).

Before this situation and the lack of spaces, vertical gardens would be a suitable element to improve residents’ welfare, because they function as an acoustic barrier by simulating a mattress which isolates the noise, mainly due to substratum’s porosity (layer of soil) and plant’s foliage. With an appropriate combination, 100% of isolation may be reached; this could be an option for the residents of municipalities near the International Airport of Mexico City, added.

Another of its advantages is the absorption of contaminants through leaves’ stomata: “These small pores allow the exchanging of carbon dioxide (CO₂), oxygen (O₂), water steam and the entrance of contaminants as nitrogen dioxides, derived from combustion”.

If these spaces are arranged facing each other, they generate a tunnel where the air recirculates by the leaves of the plants; so, the absorption of contaminants is potentiated. In addition, green walls favor the presence of birds, sparrows and starlings, which use these systems for their nests and to feed from the insects.

Jorge Escutia, also a biologist at the IE, considered relevant to incentivize in naturation systems the usage of native flora, as well as to sensitize owners and observers about phenological changes of the plants, that is, they won’t always have the same green appearance or foliage, “which is why we should appreciate the seasonal aspects and also those of growth”.

Since 1988, vertical gardens have covered European areas, thanks to the patented technique of Patrick Blanc, French biologist who applied his knowledge in botany for the creation of monumental spaces.

On that basis, Ulises Martínez, graduate from the Faculty of Engineering, undertook the commercialization of green walls through the enterprise Integral Naturation (Naturación Intergal), incubated at InnovaUNAM and partially funded by the National Council of Science and Technology. It is linked to the Chapingo College of Postgraduates and the IE, where Saraí and Jorge collaborate.

As a result of this association, two gardens have been installed in the university entity, one with native plants from the Mexico Valley and another, experimental, which supports the development of a master thesis. With the first one, improvements are expected by making the system less expensive, selecting appropriated species for outdoor and indoor gardens, and also by designing and testing substrata and nutritional formulas, detailed Martínez.

That vertical garden’s installation consisted on an iron frame on which was fixed a waterproof plate made of plastic and recycled aluminum, which isolates and protects the wall from moisture. Two layers of geotextile, a plastic fabric which allows the growth of roots and water filtering; finally, there was placed a mixture of substrata which provides humidity retention, as well as good drainage and support to the root.

By last, he commented that this is an example of how university people may generate business and work in collaboration with other professionals in order to resolve technical aspects of naturation systems.

Source: El Occidental journal. http://www.oem.com.mx/eloccidental/notas/n3641124.htm. Translated by Belem Ruiz (Edition and Communication, PIT-UAS).