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Rani Prihatmanti and Nooriati Taib
3rd International Conference-Workshop on Sustainable Architecture and Urban Design 2017
ICWSAUD2017
Biofaçade as a Vertical Edible Landscape in High-Rise Building: A Review
Rani Prihatmanti*, Nooriati Taib*
*Department of Architecture, School of Housing, Building & Planning, Universiti Sains Malaysia,
MALAYSIA
A R T I C L E I N F O
A B S T RA C T
Article history:
Received 23 August 2017
Received in revised form
23 September 2017
Accepted 30 October 2017
Available online
13 November 2017
Keywords:
Biofaçade
Vertical Edible Landscape
Food Security
Transitional Space
High-Rise Building
This paper reviews the potential of biofaçade as one of the
Vertical Greenery Systems (VGS) for addressing the food
security issue in the urban context. The emergence of biofaçade
has led many scholars in conducting many studies on the benefits
of greeneries on the building. Besides reducing the temperature,
biofaçade could be optimized as a vertical edible landscape. The
scarcity of landed green space in the urban initiates the experts in
growing edible plants on the high-rise building. Transitional
space, or buffer space, is a space with less economical value.
Regardless to that, the presence of transitional space is important
and could be optimized as a green space. The review concludes
there are many factors needs to be concerned in growing edible
plants on the high-rise building. Those factors are the plant type,
the climatic condition on the high-rise building, maintenance, and
pest issue. The result also shows that by growing edible
biofaçade in the high-rise building, it could increase the vegetable
consumption, lower the emission of fossil fuel for transportation,
minimize the pesticides used, and it will reduce the expenditure
on fruits and vegetables.
1 Introduction
Food is one of the primary needs for all mankind and is a key aspect of most cultures and
has contributed to and inspired many creative aspects of our lives from local cuisine to urban
form (Gorgolewski, 2008). Over the years, the activity to fulfill this requirement has created
an evolution in human settlements and cultures. The issue of safe food on the table is a never-
ending concern for the government, particularly in the developing countries. This concern is
also triggered by the increasing population growth rate resulting the decreasing amount of
2011 ICWSAUD2017
*Corresponding author (R. Prihatmanti). E-mail addresses: rani.peanut@gmail.com.
363
land for food production in the urban area. This will cause the source of food production is
relatively far from the urban, and this will increase health hazard due to the need of using
chemicals to prolong the post-harvest life (Tayobong et al., 2013). He also stated that the most
vulnerable to the food security is the depressed communities. The issue about food
availability is expected to raise awareness of the government and the public to produce safe
and readily available food. Therefore it needs to investigate an alternative method to supply
food to the urban community in a sustainable manner.
One possible idea is by growing food plants vertically, or known as vertical farming.
According to (Al-chalabi, 2015), the concept of a vertical farm is growing fruits, vegetables,
and grains inside the building on the urban setting. This is also inline with Despommier
(2009) that defines vertical farm as a large-scale extension of urban agriculture within a
building. It is expected to provide food supply for the 60% urban people who will be
migrating to the cities in the year 2030 (Despommier, 2013). It could be concluded that
vertical farming is growing edible plants within a building. The basic system and technology
can be a guiding principle in establishing edible landscaping (EL). Edible landscaping could
be defined as the use of food-producing plants in the landscape. It could be a combination of
fruit and nut trees, edible flowers, berry bushes, vegetables, and herbs along with ornamental
plants to create an aesthetically pleasing landscape design.
According to Naranja (2011), edible landscape is a combination of science and creativity
to create an integrated food production technology. EL is not merely about crop production, it
involves several complex activities: planning, design, implementation, and maintenance
(Tayobong et al., 2013). The common application of EL is on a horizontal plane. However,
due to the land scarcity, vertical edible landscape could be a promising solution in providing
accessible food. Edible plants are grown vertically as in the Vertical Greenery System (VGS),
be it is living wall system or green façade. Perini et al. (2011) define living walls are growing
plants from a modular panel that contains natural or artificial growing medium on each of its
panel and using the hydroponic system to provide the plants’ water and nutrition. While green
façade is greening the wall by growing plants directly or indirectly from the ground or planter
box. Hence, this paper highlights the potential of vertical EL in the urban setting focusing on
the tropical climate. With its abundant sunlight and rainfall, tropical countries have wide
possibilities to maximize the agriculture growth. By growing our food near to us, we can
reduce the food dependency from imported sources. This could be done with the application
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Rani Prihatmanti and Nooriati Taib
of VGS in building such as biofaçade.
2 Biofaçade as Vertical Edible Landscape
Biofaçade is categorized as vertical greenery system (VGS), which is also known as
vertical garden, green wall technologies, or vegetated façade. There are many similar terms,
phrases or keyword of biofaçade established by the previous researchers. As stated by
Sunakorn and Yimprayoon (2011) biofaçade could be defined as a vertical climbing plant.
Another term was defined by Lam, et al. (2005) and Ip (2009), which used the term bioshader
instead of biofaçade although the meaning is similar. According to them, bioshader is a bio-
shading device using a vertical layer of deciduous climbing plant canopy that trails on a metal
framework, which is mounted external to the façade.
Biofaçade could be an alternative for urban farming where food plants are grown
vertically since the land is gradually limited. Rapid urbanization, climate change, and land
scarcity trigger the food security issues for the food demand in the future. Besides providing
food, biofaçade is significantly proven to lower the temperature as well as sequestering the
Carbon level. The Kyoto Protocol has stated that there is a need to limit the greenhouse gas
emissions as well as to develop the carbon dioxide sequestering technologies. United Nation
Framework Convention on Climate Change (UNFCCC) also determined that carbon dioxide
is the strongest gas effect on the climate change and plants are known to have the ability to
help offsetting the carbon emission (United Nations, 1998). The data on Table 1 describes the
previous studies on incorporating edible and/or medicinal plants as a biofaçade in the tropical
climate context.
Table 1. Previous research on biofaçade as a vertical edible landscape
Author
Plant used
Biofaçade system
Result
Sunakorn &
Yimprayoon
(2011)
Location:
Bangkok,
Thailand
- Blue trumpet vine
(Thunbergia
grandiflora)
- Ivy gourd (Coccinia
grandis)
- Mexican creeper
(Antigonon leptopus)
Green façade:
Indirect greening
system with
planter box
Air temperature
reduced by max.
4.71oC
Rahman, Yeok,
& Amir (2011)
Location:
Penang, Malaysia
Winged bean
(Psophocarpus
tetrogonobulus)
Green façade:
Indirect greening
system with pots
Outdoor wall surface
temperature reduced
by maximum 11oC
*Corresponding author (R. Prihatmanti). E-mail addresses: rani.peanut@gmail.com.
365
Amir et al. (2011)
Location:
Penang, Malaysia
- Winged bean
(Psophocarpus.
tetrogonobulus)
- Kidney bean
(Phaseolus vulgaris)
- Long bean (Vigna
unguiculata
sesquipedalis)
- Sweet pea (Pisum
sativum)
Green façade:
Indirect greening
system with pots
Four Legume plants
are suitable for
biofaçade application
in hot and humid
climate
Safikhani,
Abdullah, Ossen,
& Baharvand
(2014)
Location: Johor,
Malaysia
Blue trumpet vine
(Thunbergia
grandiflora)
Green façade:
Indirect greening
system with
planter box
Living wall:
Modular with
trellis
- The living wall &
green façade can
reduce indoor
temperature up to 3oC
& 4oC respectively
- The living wall and
green façade reduce
the wall cavity
temperature by 8oC
and 6.5oC respectively
Amir et al. (2014)
Location:
Penang, Malaysia
Winged bean
(Psophocarpus
tetrogonobulus)
Green façade:
Indirect greening
system with pots
Average of carbon
sequestration 2.35
μmole CO2 m-2 s-1
was converted to kg
CO2 per year per m2,
equal to 9357.83 kg
CO2 year-1 hectar-1
Basher et al.
(2016)
Location:
Penang, Malaysia
Winged bean
(Psophocarpus
tetrogonobulus)
Green façade:
Indirect greening
system with
planter box
Maximum surface
temperature drop until
6.4oC
Based on the previous research, Legume plants such as Winged bean (Psophocarpus
tetrogonobulus), Kidney bean (Phaseolus vulgaris), Long bean (Vigna unguiculata
sesquipedalis), and Sweet pea (Pisum sativum) are suitable to be grown as a biofaçade of a
building in the tropical climate (Amir, et al. (2011); Basher, Rahman, & Zaman, (2016)). The
Winged bean plant is proven could reduce the outdoor wall surface temperature by maximum
11oC by climbing it on the wall using metal diamond fence as a support (Rahman et al., 2011)
and effective in in sequestering Carbon level up to 9357.83 kg CO2 year-1 hectar-1 (Amir et al.,
2014). Another study conducted by Basher et al. (2016) by using the same plant which was
planted by indirect greening system with planter box. The result shows that the maximum
surface temperature could decrease until 6.4oC due to the shade provided by the leaves.
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Rani Prihatmanti and Nooriati Taib
Sunakorn and Yimprayoon (2011) also conducting research by growing three different
medicinal climbing plants: Blue trumpet vine (Thunbergia grandiflora), Mexican creeper
(Antigonon leptopus), and Ivy gourd (Coccinia grandis). These plants were grown indirectly
with planter box. The finding shows that Blue trumpet vine (Thunbergia grandiflora) could
reduce the air temperature by maximum 4.71oC. Hence, it could be concluded that by creating
living and growing space in a dense vertical format, it will reduce the need for reduce food
travel distance, create a living architecture that is part of an urban ecosystem, as well as
improving the thermal comfort. Besides as a microclimate modifier and food supplier,
Tayobong et al. (2013) stated that edible biofaçade could increase the diversity and promote
the use of endemic plant species. Furthermore, it could be an additional source of income by
selling foods for the community.
3 Growing Vertical Edible Landscape on Transitional Space in High-
Rise Building
Due to the space limitation, the urban dwellers are now occupying the high-rise
residential buildings with limited access to the greeneries. Transitional space, or buffer space
could be defined as a space in between the interior and exterior environment. Although this
space has less economical value, transitional space has the potential to be optimized in
replacing the greeneries on the ground floor since it is often related with open area. Thus it is
easily influenced by the variable weather conditions since it is close to the natural
environment. It is expected that by integrating vertical plants on building, it could help to
filter out the airborne pollutants as well as to improve the thermal comfort.
Figure 1. Possible application of biofaçade in balcony
Visual cone
*Corresponding author (R. Prihatmanti). E-mail addresses: rani.peanut@gmail.com.
367
Source: Prihatmanti & Taib (2017)
In the high-rise building, balcony could be utilized as a green space. Moreover, balcony
is the most accessible and privately owned transitional space. In Figure 1, it illustrates the
application of biofacade in a balcony (Prihatmanti & Taib, 2017). The biofaçade will be
attached on each side of the wall, thus it will not obstruct the view as illustrated on the visual
cone. The view of scenery outside the balcony should be maintained since it will be a stress-
reliever for the occupants. Since years, people have been attempting to integrate plants to the
building. The effect of plants in building is undeniable. Beside as a climate modifier and food
supplier, plants could significantly affect the psychological condition of the building
occupants. A study by Taib & Abdullah (2012) resulted that the presence of landscape in
high-rise building could bring a therapeutic effect. Based on the survey conducted, the
building occupants mostly use the landscape in order to take a short break from the work
(resting), to get some fresh air, to enjoy the company of others, and to enjoy the landscape
provided. Wong, Tan, Tan, Sia, & Wong (2010) also agreed that VGS are able to increase
visual interest to plain walls and roofs, as well as beautifying the urban environment with a
living art. Moreover, VGS could rejuvenate and revitalize the building occupants who are in
contact with the greeneries. It is also proven that access to outdoor greenery can help reduce
stress levels in our hectic urban lifestyle, thereby promoting a more efficient workplace.
4 Key Success Factors
Vertical edible landscape is an innovative concept of space management that uses edible
plants to substitute ornamental plants commonly used in conventional landscaping. In vertical
edible landscape, edible plants can be intercropped with other ornamental plants and planted
in accordance with the design. To create a successful vertical edible landscape, Gorgolewski
(2008) stated there are five factors to consider: available spaces, climate, topography, soils,
needs of the community. However, according to Tayobong et al. (2013), the key for
successful cropping is the selection of desirable species, varieties, and cultivars. The desirable
crops should be resistance to pests and diseases, high yield, and adaptable with the wide range
of soil and climatic conditions.
Generally, edible landscape consists of fruit trees, vegetables, cereals, and herbs, which
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serve as screens, accents, hedges, and ground covers in the landscape (Tayobong et al., 2013).
Since this paper is focusing only on biofaçade, which is only planted on the high-rise
building, thus only the climbing plants are reviewed. Plants that have medicinal properties
could be considered as well. Many studies have been conducted on edible biofacade as stated
on Table 1, those plants are Kidney bean (Phaseolus vulgaris), Long bean (Vigna unguiculata
sesquipedalis), Sweet pea (Pisum sativum), Blue trumpet vine (Thunbergia grandiflora), Ivy
gourd (Coccinia grandis), Mexican creeper (Antigonon leptopus), and Winged bean
(Psophocarpus. tetrogonobulus). Moreover, Tayobong et al. (2013) suggested that Bitter
melon (Momordica charantia), Cucumber (Cucumis sativus), and Sponge gourd (Luffa
cylindrical) are recommended to be applied on small-scale edible biofaçade. These plants are
selected based on the adaptability to the site for crop production technique.
Basher et al. (2016) recommends Winged bean (Psophocarpus. tetrogonobulus) to be
applied in biofaçade due to its ability to withstand the heat gain from long sun exposure. It is
known that Winged bean plant has longer lifespan due to the capability in storing sufficient
nutrients in the tuberous root for a period of time. Another research that has been conducted
by Amir et al. (2011) recommend that Legumes are suitable to be applied in biofaçade due to
its drought tolerance to suit the different growing conditions especially if planted in the
tropical climate. Legumes are considered as an easy-growing plant and it requires fertile soil
with good drainage to prevent water logging. Moreover, Leguminous plants have the
symbiotic property associated with Nitrogen-fixing Rhizobium in its root nodules resulting
Nitrogenous-fertilized soil. This symbiosis could reduce the maintenance cost in terms of
fertilization as well as to ensure the sustainability of the biofaçade.
To be applied in tropical countries, plants must able to withstand the hot and humid
conditions. Hopkins and Goodwin (2011) emphasized on the importance for selecting suitable
plants before application, particularly when applied in different weather conditions. Climatic
conditions need to be taken into account when applying biofaçade in high-rise building since
plant growth is fully depending on the quality of the climate. The wind velocity and heat
intensity strongly affect the growth performance of plants. Will and Burch (1984) also stated
that building orientation determines the intensity of the light that is crucial in the
photosynthesis process. The East-facing area receives the morning sun for few hours, which is
ideal for the plants. This is also agreed by Amir et al. (2011), Legume plants should be
planted facing the morning sunlight as this is the best radiant for food production. However,
*Corresponding author (R. Prihatmanti). E-mail addresses: rani.peanut@gmail.com.
369
late morning sun may begin to cause heat problems, which might affect the plants. On the
other side, West-facing area receives the highest amount of daylight as well as the heat.
Therefore, biofaçade that grows on a transitional space, such as balcony, must able to tolerate
the high light intensities. Another concern for plants that grow in container, it will dry out
faster because of the limited amount of growing medium, especially when the intensity of the
heat and wind is high (Tayobong et al., 2013). To reduce the hassle in conventional farming
caused by the climatic factors, hydroponic and aeroponic systems are currently in the trend for
growing with soil-less system. Besides of the easy maintenance, these systems could increase
the yield by more than 23 times and decreasing the water usage up to 30 times compare to
conventional farming (Despommier & Ellingsen, 2008). The environmental factors could be
elucidated by (1) evaluate the climate condition on the location, (2) select the most suitable
plants including the growing media, and (3) structural modification, if possible.
5 Maintenance
Regular maintenance is very crucial since plants are living things that may lead to
overgrown species or die. Regular watering is required and it should not excessively water
that could harm plants and triggers the unwanted species to grow. The less exposure to the
daylight also contributes a negative effect, where plants could not optimally grow. However,
excessive daylight also might be harmful to the plants themselves. Good landscape criteria
should fulfill its function with efficiency, aesthetic value, enhances the welfare, and can be
maintained in a viable condition. Hence, maintenance is important to maintain the growth
performance and the yield, where yield is a priority in vertical edible landscape. Some simple
practices conducted during maintenance are watering, pruning, fertilizing, harvesting, and
management of pests.
Planting biofaçade in transitional space such as in the balcony are still at the risk being
attack by pests and diseases. The use chemical pesticides and herbicides as a pest
management are widely applied and easy to use. However, it will bring the short and long
term adverse effects to the environment as well as to the human. Chemicals with natural
extracts, such as Citronella (Cymbopogon nandus) liquid could be considered as an alternative
to halt pests (Amir et al. 2011). Fertilizer made from excrement should be avoid to prevent the
spread of numerous viral, bacterial, and eukaryotic infectious agents (Despommier, 2013).
Tayobong et al. (2013) suggested companion planting could be applied as one of the pest
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Rani Prihatmanti and Nooriati Taib
management practices. It is known that onion, Marigold (Tagetes spp.), and garlic are
repellent plants that are commonly used in companion planting to repel pests.
6 Conclusions
Rapid urbanization has caused the emergence of high-rise buildings in the urban area and
the green spaces on the ground lever are gradually diminishing. This phenomenon has initiate
many people to integrate the greeneries with the building regardless the limitation of the space
allocated. This subject has attract attentions among the researchers and related professional in
combining edible and medicinal plants as a biofaçade, which is planted on a transitional space
in high-rise building. Providing food to accommodate the basic human need now is possible
in an urban context in a way that is socially, economically, and ecologically manner. The
main objectives of edible landscaping in the urban is to engage the community in growing
their own vegetables by having their own sources of food even at the smallest scale possible
and at the end it would increase vegetable consumption. Growing food plants in the urban will
lower the consumption of fossil fuel for transportation, decrease the pesticides used, as well as
to reduce the expenditure on fruits and vegetables.
The presence of edible biofaçade in building are known to provide benefits, it could
modify the microclimate that could reduce the energy consumption, filter out pollutants,
provide food in small scale, a sustainable aesthetic element and also as a stress reliever.
However, there are some issues that need to taken into account, those are the regularity of
maintenance and handling the pest problem. The location of the edible biofaçade will
determine the most appropriate plant species to be planted to prevent from the abiotic stress
which may impacting the growth performance.
7 Acknowledgements
The authors would like to thank to the Universiti Sains Malaysia as the funding body of
this research under the USM Fellowship scheme as well as the University Grant no.
1001/PPBGN/814286.
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Authors’ Profile
Nooriati Taib was born in Kuala Lumpur, Malaysia in 1985. She received a bachelor degree of Housing,
Building & Planning (majoring in Architecture) and bachelor of Architecture from the Universiti Sains
Malaysia in 2007 and 2009, respectively. She later obtained her Ph.D. degree under Architecture programme
in the field of environmental design (thermal comfort) in 2015. She joined Architecture Programme, under
School of Housing, Building & Planning, Universiti Sains Malaysia, as a lecturer in 2015. Her current
research interests include thermal comfort, biofaçade, transitional spaces in high-rise building and the effects
of landscape on thermal comfort.
Rani is currently a Ph.D. candidate in the Architecture Department in Universiti Sains Malaysia. She obtained
her bachelor and Master degree both in Interior Design. Her concern on occupants’ well-being in the built
environment has brought her on conducting research focusing on the Indoor Environmental Quality (IEQ),
Indoor Air Quality (IAQ), Post Occupancy Evaluation (POE), human comfort, and adaptive reuse of heritage
buildings.