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Biowalls—The Vertical Garden
Earth Talk® is written and edited by Roddy Scheer and Doug Moss and is a registered trademark of E-The Environmental Magazine
Green walls (also known as biowalls, vertical gardens or vertical vegetated complex walls) are wall structures
partly composed of or filled in with growing plant matter.
More than just easy on the eyes, green walls work like green
roofs by filtering air and water, soaking up carbon dioxide and
helping lessen the “heat island” effect of
urban areas while reducing air conditioning costs in their host buildings.
The self-proclaimed creator of the
vertical garden concept, French botanist
Patrick Blanc, pioneered the use of
hydroponic cultivation techniques—
plants grow in an irrigated mineral nutrient solution without the need for a
soil substrate—to create large green wall
installations in both residential settings
and within larger public structures and
even office buildings from Singapore to San Francisco and
points in between.
Blanc’s installations start by placing a metal frame on a
load-bearing wall or structure. The frame supports a 10-
millimeter-thick PVC plate, upon which are stapled two
three-millimeter-thick layers of polyamide felt. “These layers
mimic cliff-growing mosses and support the roots of many
plants,” he says, adding that a network of pipes and valves
provides a nutrient solution of dissolved minerals needed for
plant growth. “The felt is soaked by capillary action with this
nutrient solution, which flows down the wall by gravity.”
“The roots of the plants take up the
nutrients they need, and excess water is
collected at the bottom of the wall by a
gutter before being re-injected into the
network of pipes. The system works in a
closed circuit.” Plants are chosen for their
ability to grow in this type of environ-
ment and depending on available light.
“Each vertical garden is a unique wall
composition of various types of plants
that has to take into account the specific
surroundings of the place in which it
is created,” says landscape architect Michael Hellgren, who
founded the firm Vertical Garden Design in 2004. “It is not
only the colorful interplay between the plants on a ‘green
wall’ that is fascinating, but also the appearance of the wall
itself, which changes daily.”
Hellgren, who has designed and implemented large green
Each vertical garden
is a unique wall
composition of various
types of plants that
has to take into
account the specific
surroundings of the place
in which it is created.
©IS TOCKPHOTO. COM/ARPAD BENEDEK; EARTH TALK
