2. WHAT IS URBAN AGRICULTURE?
The World Health Organisation defines food security as being when all people at all times have access to
sufficient, safe, nutritious food to maintain a healthy and active life (1996, para. 1). Food insecurity is a
notion primarily associated with developing countries; it is seen as something that is very far removed from
the typical urban lifestyle. However, population growth and the Global Financial Crisis have led to an
increase, in recent years in the number of people in Western countries being faced with the issue of not
having access to a sufficient and reliable food source. The growing population, the resulting urban
expansion, and a rapidly increasing demand for food is causing many to seek alternative means of primary
production. It is from this that the idea of Urban Agriculture developed.
Urban Agriculture is, essentially, the production of fruits, vegetables and herbs, as well as livestock raising, in
an urban environment (Hodgson, et al., 2011). Urban Agriculture has many facets; it can range from
Community Gardens and Roof-top Gardens, to Aquaponics, to Vertical Farming and to Peri-Urban farming.
The recent ideological shift in society to move towards greener and more sustainable ways of living has
resulted in an increase in Urban Agriculture. However, there is one major question that stands unanswered in
the debate surrounding Urban Agriculture and its capabilities – can Urban Agriculture be used to ensure
urban food security?

3. ROOFTOP GARDENS
The notion of using empty rooftops to grow produce, termed Rooftop Gardening, is coming into vogue all over the world as
increasing numbers of people are discovering this more economical and sustainable method of farming. Rooftop Gardens have a
number of social and environmental benefits; the presence of a Rooftop Garden on a building increases its value, additionally, it
supports the idea of urban food production (City Farmer, 2003). The plants being grown in Rooftop Gardens aid in improving the
quality of the surrounding air by reducing Carbon Dioxide levels (Spivey, 2002: p.668).Furthermore, having a garden on the roof of
a building means that the need for internal temperature control is reduced as the Garden provides a layer of insulation (Harazono,
et al., 1991). The roofs are lined with a drainage layer, followed by a waterproof membrane, a growing medium, and then the
plants (Spivey, 2002, p668). When the plants transpire, and the water evaporates from the leaf surface into the surrounding air,
the temperature of the immediate environment is reduced (Spivey, 2002, p668). Canada’s National Research Council reported that
the Rooftop Garden at its Ottawa campus reduced the heat entering the building by as much as 85% on summer days (Spivey,
2002, p668). However, one major drawback to Rooftop Gardens is the initial cost to set them up, particularly if the rooftop in
question requires reinforcement. To combat this, financial incentives are being provided for builders to install Rooftop Gardens.

4. Rooftop Garden on Chicago City Hall
Chicago’s Lurie Garden is a prime example of a Rooftop Garden; spanning 5 acres, this garden sits on top of
the Millennium Parking Garage and has become a very popular site for recreation and relaxation in
downtown Chicago. The site sees around 4 million visitors each year, exposing a large demographic to the
garden’s environmentally sustainable image; the garden uses no chemicals, minimal amounts of water, and
compost tea in place of fertiliser.
Photo courtesy of Yognews (http://yognews.blogspot.com.au/2010/08/green-roof-system-on-chicago-city-hall.html)

5. ROOFTOP GARDENS
The notion of using empty rooftops to grow produce, termed Rooftop Gardening, is coming into vogue all over the world as
increasing numbers of people are discovering this more economical and sustainable method of farming. Rooftop Gardens have a
number of social and environmental benefits; the presence of a Rooftop Garden on a building increases its value, additionally, it
supports the idea of urban food production (City Farmer, 2003). The plants being grown in Rooftop Gardens aid in improving the
quality of the surrounding air by reducing Carbon Dioxide levels (Spivey, 2002: p.668).Furthermore, having a garden on the roof of
a building means that the need for internal temperature control is reduced as the Garden provides a layer of insulation (Harazono,
et al., 1991). The roofs are lined with a drainage layer, followed by a waterproof membrane, a growing medium, and then the
plants (Spivey, 2002, p668). When the plants transpire, and the water evaporates from the leaf surface into the surrounding air,
the temperature of the immediate environment is reduced (Spivey, 2002, p668). Canada’s National Research Council reported that
the Rooftop Garden at its Ottawa campus reduced the heat entering the building by as much as 85% on summer days (Spivey,
2002, p668). However, one major drawback to Rooftop Gardens is the initial cost to set them up, particularly if the rooftop in
question requires reinforcement. To combat this, financial incentives are being provided for builders to install Rooftop Gardens.

6. PERI-URBAN FARMING
Peri-urban Agriculture involves the production of food on the peripheral areas of cities and towns. It can range from small- to
large-scale activities, both commercial and non-commercial and involves horticulture and livestock production and often operates
in a complementary manner to rural agriculture practices.
Peri-urban Agriculture improves the availability and affordability of nutritious food to urban dwellers, especially of those in low
socio-economic areas. Additionally, Peri-urban Agriculture also benefits the environments through recycling wastewater by using
it as a source of nutrients for crops, and for watering livestock. Wastewater is highly beneficial for agriculture due to its high
nutrient concentration, which, in combination with proper management in regards to its usage, can reduce the need for the
application of fertilizers in Peri-urban Farming. The spaces being cultivated also aid in improving bio-diversity and reducing carbon
dioxide levels, thereby reducing the impact on climate change – something affecting food security around the world.
In developing countries Peri-urban Agriculture provides both food and job opportunities for people from low socio-economic
backgrounds. In some parts of Africa, over 20,000 people are estimated to be involved in the processing and marketing of Peri-
urban Agriculture (Cofie, 2010). Peri-urban Farming provides a number of social benefits for people in low socio-economic areas
ranging from an increased income, reduction of expenditure on food, and a reduced dependence on imported food, all of which
combine to reduce vulnerability in regards to food price fluctuation and availability.

7. COMMUNITY GARDENS
Community Gardens are publicly functioning gardens that are maintained, managed and controlled by the surrounding
community. The produce and benefits go directly to that community and the land used is typically owned by the community, the
local government or a not-for-profit organization. Newer housing estates and subdivision projects are beginning to notice the
importance of community gardens, along with the socio-economic and health benefits they promote and, as such, many cities are
beginning to incorporate them into plans and designs. A major benefit to them is that they are relatively easy to establish in
already developed areas provided that the community has the capacity to maintain the garden and that there is land available.
Community Gardens are particularly relevant in developed areas with the means to properly maintain the garden. In cases such as
these, the garden plays a much more subtle role than trying to solve food insecurity problems, rather it simply gives the people of
the community a direct source of nutritional food, carbon absorption, and a connection to their environment; Community
Gardens can have quite a dramatic positive effect on the values of land and houses in the surrounding community (Voicu and
Been, 2008, pp 242-283).
One of the biggest problems preventing the establishment of Community Gardens is the lack of available land, or the funds with
which to purchase it. Additionally, it is difficult to ensure that the community will correctly maintain and use the garden;
organisations are reluctant to commit funds and resources if they are not fully convinced of the benefits of establishing a Garden
in a particular community. Community support also plays a major role, as it is the community itself that must maintain the Garden
and ensure that it is utilized correctly. Often, local governments need to be persuaded to allocate arable land, and in new housing
estates free blocks must be reserved.

8. TECHNOLOGIES
HYDROPONICS AQUAPONICS DESIGN

9. Hydroponics
Hydroponics is the growing of plants
without soil, instead using water, nutrients,
aeration and light (Stauffer, 2006). In this
system the nutrients are added to the
water and then absorbed by the plants.
Hydroponic systems can prove superior to
traditional soil agriculture in several ways.
They use far less water as the only water
lost is due to evaporation, plant absorption
and from changing the water to limit salt
build up (Bernstein 2012, p50).
Hydroponics can produce far larger yields
using a significantly smaller land space. In
the case of the Hydroponic Rotating
Growing System, ‘the production is
equivalent to 5000m2 of strawberry plants
in the ground on a 75sqm footprint’ (O’Dea
2013, p 14). Hydroponic crops are also
almost completely free from soil pests and
diseases, however nutrient levels must be
carefully monitored so as to ensure the
plants do not suffer from a lack of
Photo courtesy of Safe Water for Kenya (http://waterkenya.wordpress.com/technology/agricultural)/ nutrients or overnutrification. Additionally,
plants can be affected by pythium (root
rot).

10. TECHNOLOGIES
HYDROPONICS AQUAPONICS DESIGN

11. Aquaponics
Aquaponics is where plants and fish are cultivated
in a sustainable, symbiotic system (Bernstein
2007, p47). It is a combination of Hydroponics and
Aquaculture (the growing of aquatic floral and
faunal organisms under controlled conditions
(Pokrant 2010, p39)). In this system, as shown in
the diagram the waste produced by the fish
provides the ammonia for bacteria and worms to
allow them to convert it into nitrites. The nitrites
are then converted into nitrates and fertilise the
plants, which filter the water before it is
transferred back to the fish.
Whilst having many of the same benefits as that of
a Hydroponic system, an Aquaponic system has far
fewer problems. Once the bacteria cycle of the
system has taken a hold and has become self-
regulating the nutrient levels only need to be
checked sparingly and, since the system is self-
enriching, the cost of chemical nutrients is
replaced with the cost of fish feed (Bernstein
2012, p50). Aquaponics uses even less water than
Hydroponics as there is no build-up of salt or
chemicals due to ‘a natural nitrogen balance that is
the hallmark of an established
ecosystem’(Bernstein 2012, p50). Aquaponics also
has a higher yield from a smaller area of
production, with one lettuce farm producing the
(The Aquaponic Source, 2013)
equivalent of a 1ha conventional farm in a 260m2
area (Gordon 2009).

12. TECHNOLOGIES
HYDROPONICS AQUAPONICS DESIGN

13. Design
Two Aquaponic systems incorporating Wall Gardens and Aesthetic Design (Ecolicious 2011)
As Hydroponic and Aquaponic systems become more feasible and available to the public, a push for more
aesthetically pleasing system designs is gaining momentum. While companies like Aesthetic Hydroponics
are making small, affordable and aesthetically pleasing indoor hydroponic systems, others, like Ecolicious,
are creating outdoor Aquaponic Systems that act as feature pieces of a garden or outdoor setting.

14. TECHNOLOGIES
HYDROPONICS AQUAPONICS DESIGN

16. Milano Santa Monica Green City
Architecture and Design incorporation:
There has been a push, in recent years, for architecture and urban design to be more eco-friendly and more
environmentally sustainable; a result of this is the increased inclusion of Urban Agriculture in the urban cityscape.
At its most simplistic, balconies and windowsills are being used to grow various vegetables, fruits and herbs; in
fact, such purpose built design aspects can improve the value of a building (Doron, 2005). Similarly, Rooftop
Gardens have recently come into vogue; in cities with high land value and high population density the most
economically viable option, in regards to Urban Agriculture, involves utilising the only free space available –
rooftops (Doron, 2005). Regardless of the form that it takes, Urban Agriculture has become an important aspect
of the cityscape, having been incorporated into many areas of urban design from as landscape architecture, to
interior design.
(Images from Exampleof.com and inhabitant.com)

18. VERTICAL FARMING
Vertical Farming, the idea of growing food upwards, instead of
outwards, is a rather recent development. One of the world’s leading
researchers into Vertical Farming, Professor Dickson Despommier from
the University of Columbia, is of the belief that Vertical Farming has the
potential to be the main source of food production in urban areas. A
farm, only one square block at the base, but 30 stories high, could yield
as much as 2,400 outdoor acres (Despommier, 2009). Food grown
indoors, in a controlled environment, eliminates concerns in regards to
flooding and droughts, as well as infectious diseases. Additionally, the
use of artificial lighting means that these farms can operate year-round
meaning that one indoor acre is worth, on average, around four to six
outdoor acres (Alters, 2007).
A Canadian architect, Gordon Graff, designed a Vertical Farm for
Toronto’s CBD. It is 58 floors high and has 8 million square feet of area
available for growing; this farm alone could feed 35,000 people each
year (Alters, 2007), and just 160 farms of this size could feed the
entirety of New York (Walsh, 2008). Some of the technologies being
utilised in this approach include hydroponics, aeroponics, drip
irrigation, artificial light technologies, and the harnessing of natural
light. By using these technologies in combination, crops are being grown
more efficiently, requiring less water, energy and time to reach
maturity.
Continue reading…
Gordon Graff’s Vertical Farm design (Alters, 2007)

19. VERTICAL FARMING
Furthermore, Vertical Farming is much more environmentally friendly than traditional farming methods; at
present, farming accounts for 20% of all fossil fuel consumption in the United States (Despommier, 2009).
Growing food locally reduces the food mile and means that the use of machinery requiring fossil fuels,
including transport, is significantly reduced, affecting not only the Carbon Footprint, but also the price of food.
The major problem with Vertical Farming is the competition when it comes to real-estate; when it comes to
occupying land area in New York City, often an investment banker is more highly valued than a tomato. In
spite of this criticism, Vertical Farming is slowly taking hold in cities around the world.

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Back

23. Case study of the Brooklyn Grange
The Brooklyn Grange is the world’s largest rooftop farm
(Brooklyn Grange, 2012); it exists in a 40,000 square foot
space on top of a six-story warehouse, situated in Long
Island City (Leahy, 2011). The farm, which first began in
the spring of 2010, outputs over 40 species of agricultural
crops ranging from tomatoes and kale, to carrots and
fennel (Leahy, 2011). The crops produced on the farm are
sold to community members, local restaurants and
grocery stores, and the owners have recently
incorporated an aviary to harvest honey. The farm is run
as a fully functioning business, with aims to provide a
sustainable model for Urban Agriculture, to provide
healthy and nutritious produce to the local community,
and to benefit the environment (Brooklyn Grange, 2012).
The produce, which is all completely organic, is grown in
soil 8 to 12 inches deep (Brooklyn Grange, 2012). The soil,
termed ‘Rooflite’ by its Pennsylvanian supplier, consists of
compost, for organic nutrients, and porous stones, which
reduce the weight of the soil and, when they break down,
provide minerals for the plants (Brooklyn Grange, 2012). Cyrus Dowlatshahi, http://www.inhabitat.com
In addition to this, no synthetic or chemical herbicides,
fertilisers or pesticides are used.
There was some concern that the pollution from the city
would manifest itself in the produce. However, the life
span of the plants, unlike that of humans, is too short for
them to be affected by the air pollutants. On the contrary,
the presence of the plants actually improves the quality of
the air as gases, such as Carbon Dioxide, are absorbed by
the plants (Brooklyn Grange, 2012).

25. THE SCIENCE BEHIND URBAN AGRICULTURE
Urban Agriculture is, for the most part, viewed as a greener and more sustainable method of producing food.
At present, agriculture in rural areas uses, and thereby contaminates, 70% of the world’s fresh water supply
(Despommier, 2009). Most Urban Farming systems are, by contrast, highly efficient; they utilise recycled
wastewater, require less space and resources, and the crops mature at a much faster rate than that of
conventional farming (Despommier, 2009). One city block, only 30 stories high, could potentially yield as much
as 2,400 acres using conventional farming techniques, with a significantly reduced environmental impact
(Despommier, 2009).
A study undertaken by Harazono, et al., (1991), looking at the efficiency of a fully sustainable rooftop garden,
found that the crops being produced grew at a similar, if not better rate, than those grown using conventional
farming methods. The effectiveness of the garden as an integrated aspect of the building was also
investigated; the garden aided in reducing the thermal load on the building during periods of warmer climate.
The study also observed an improvement in the quality of the air in the vicinity of the garden. Harazono’s
study, despite being over two decades old, is one of very few published scientific undertakings in the field of
Urban Agriculture. As such, the full scientific ramifications of Urban Agriculture, in regards to its
environmental impact and its viability in terms of food security, is, as yet, undetermined.

26. IS IT THE ANSWER?
Urban Agriculture has many health, environmental, and socio-economic benefits, and there is no doubt that it
is a significant improvement from conventional farming. However, the real question here is whether Urban
Agriculture can be used as a means of ensuring urban Food Security.
Presently, there is very little scientific literature available on the subject of Urban Agriculture; only a handful
of reliable studies have been undertaken in regards to its efficacy and viability. As a result, it has not been
developed to its full potential; it will likely be many years yet before Urban Agriculture techniques have been
advanced to the point where they may be applied to feed whole cities. Current Urban Agriculture methods
may not be able to solve urban food insecurity, but their contribution to the improvement of living conditions
cannot be disregarded. It may not be applicable in extreme situations, however Urban Agriculture is valuable
as a supplement to rural farming.
There are those who believe that the path to food security is via even more intensive and industrialised
farming techniques. But the fact of the matter is, we simply do not have the room or the resources to
continue down the path that we are on. Something needs to change; whether it be an ideological shift to
Urban Agriculture, or a physical shift to the cities, the Earth simply cannot sustain the population in our
present state. So, while Urban Agriculture may not be the only, or even the best option, when it comes to
improving urban food security, it is a major step in the process of providing everyone with the most basic
Human Right of having access to food.