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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?

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ROOFTOP GARDENSThe 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.

Photo courtesy of Yognews (http://yognews.blogspot.com.au/2010/08/green-roof-system-on-chicago-city-hall.html)

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.

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ROOFTOP GARDENSThe 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.

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PERI-URBAN FARMINGPeri-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.

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COMMUNITY GARDENSCommunity 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.

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HYDROPONICS AQUAPONICS DESIGN

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HydroponicsHydroponics 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 nutrients or overnutrification. Additionally, plants can be affected by pythium (root rot).

Photo courtesy of Safe Water for Kenya (http://waterkenya.wordpress.com/technology/agricultural)/

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HYDROPONICS AQUAPONICS DESIGN

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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 equivalent of a 1ha conventional farm in a 260m2 area (Gordon 2009).

(The Aquaponic Source, 2013)

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Design

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.

Two Aquaponic systems incorporating Wall Gardens and Aesthetic Design (Ecolicious 2011)

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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)

Green CityMilano Santa Monica

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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, on 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.

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Gordon Graff’s Vertical Farm design (Alters, 2007)

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VERTICAL FARMINGFurthermore, 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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REFERENCES & FURTHER READINGAbdulkadir, A. (2012). "Characterization of urban and peri-urban agroecosystems in three West African cities".International journal of agricultural sustainability , 10 (4), p. 289. Alter, L. (2007). Sky farm proposed for downtown Toronto. Retrieved from http://www.treehugger.com/sustainable-product-design/sky-farm-proposed-for-downtown-toronto.html Alter, L.(2008). More detail on Gordon Graff’s skyfarm. Retrieved from http://www.treehugger.com/green-food/more-detail-on-gordon-graffs-skyfarm.html Arvidson, Adam. (2010). Lurie Garden: Rooftop Wonder. 39-41. Retrieved from http://search.proquest.com.ezp01.library.qut.edu.au/docview/527846974 Ayenew, Y. A. (2011). "Socioeconomic characteristics of urban and peri-urban dairy production systems in the North western Ethiopian highlands". Tropical animal health and production , 43 (6), p. 1145 Bernstein, S (2012) Aquaponic Gardening: A Step-by-Step Guide to Raising Vegetables and Fish Together [EBL Version]. Retrieved from http://qut.eblib.com.au.ezp01.library.qut.edu.au/patron/FullRecord.aspx?p=1001193&echo=1&userid=BN0XdTI24G5ayVNC1KQEkQ%3d%3d&tstamp=1365513335&id=BEA3ADA17602D8BB5C2B36B4E3E2087B51F22AFB Brooklyn Grange (2012). About our Farm. Retrieved from http://www.brooklyngrangefarm.com/aboutthegrange/ Cabannes, Y. (2012) “Pro-poor legal and institutional frameworks for urban and peri-urban agriculture” FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS. Retrieved from: http://www.fao.org/docrep/017/i3021e/i3021e.pdf City Farmer. (2003). Rooftop Gardens. Retrieved from http://www.cityfarmer.org/rooftop59.html Cofie, O. (2010) Emerging Issues in Urban and peri-urban agriculture (UPA) in West Africa: Briefing note” International Water Management Institute. Retrieved from: http://ruaf.iwmi.org/Data/Sites/4/PDFs/UPA%20Briefing%20note.pdf Despommier, D. (2009). The rise of vertical farms.Scientific American, 301, 80-87 Doron, G. (2005). Urban Agriculture: Small, Medium, Large. Architectural Design, 75(3), 52-59.doi: 10.1002/ad.76 Dowdey, S. (2007). What is a Green Roof? Retrieved from http://science.howstuffworks.com/environmental/green-science/green-rooftop.htm Ecolicious (2011) ABC Gardening Expo - Landscape Design Challenge, Sydney [Image] Retrieved on 8 April 2013, from http://www.ecolicious.com.au/index.html Next page

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Ecolicious (2011) Manly Beach: Vertical Aquaponics [Image] Retrieved on 8 April 2013, from http://www.ecolicious.com.au/index.html Firth, C., Maye, D., Pearson, D. (2011). “Developing ‘community’ in community gardens”. Local Environment, 16(6), p. 555-568. Retrieved from http://web.ebscohost.com.ezp01.library.qut.edu.au/ehost/pdfviewer/pdfviewer?sid=e98f401a-c0fb-4b03-9d4e-0b9bbaf5041d%40sessionmgr10HYPERLINK "http://web.ebscohost.com.ezp01.library.qut.edu.au/ehost/pdfviewer/pdfviewer?sid=e98f401a-c0fb-4b03-9d4e-0b9bbaf5041d%40sessionmgr10&vid=2&hid=18"&HYPERLINK "http://web.ebscohost.com.ezp01.library.qut.edu.au/ehost/pdfviewer/pdfviewer?sid=e98f401a-c0fb-4b03-9d4e-0b9bbaf5041d%40sessionmgr10&vid=2&hid=18"vid=2HYPERLINK "http://web.ebscohost.com.ezp01.library.qut.edu.au/ehost/pdfviewer/pdfviewer?sid=e98f401a-c0fb-4b03-9d4e-0b9bbaf5041d%40sessionmgr10&vid=2&hid=18"&HYPERLINK "http://web.ebscohost.com.ezp01.library.qut.edu.au/ehost/pdfviewer/pdfviewer?sid=e98f401a-c0fb-4b03-9d4e-0b9bbaf5041d%40sessionmgr10&vid=2&hid=18"hid=18 Gordon, M (2009, September 27) Backyard Aquaponics, Honolulu Advertiser. Retrieved from http://search.proquest.com.ezp01.library.qut.edu.au/docview/414919137 Harazono, Y.,Teraoka, S., Nakase, I., Ikeda, H. (1991). “Effects of rooftop vegetation using artificial substrates on the urban climate and the thermal load of buildings”.Energy and Buildings, 15(3-4), p. 435-442. Retrieved from http://www.sciencedirect.com.ezp01.library.qut.edu.au/science/article/pii/037877889090018E# Hou, Y. (2012). "Nitrogen balances of smallholder farms in major cropping systems in a peri-urban area of Beijing, China". Nutrient cycling in agroecosystems , 92 (3), p. 347. Kurian, M. (2013). "Wastewater re-use for peri-urban agriculture: a viable option for adaptive water management?". Sustainability science , 8 (1), p. 47 Leahy, K. (2011). Brooklyn Grange is the World’s Largest Rooftop Farm!. Retrieved from http://inhabitat.com/nyc/brooklyn-grange-worlds-largest-rooftop-farm-kicks-off-second-growing-season/

O’Dea, M (2013) Postcard from … South Africa. Practical Hydroponics and Greenhouses, 129, 13-15. Retrieved from http://search.informit.com.au.ezp01.library.qut.edu.au/documentSummary;dn=179344904375051;res=IELHSS Pokrant, B (2010) Aquaculture, Green Food: An A-to-Z Guide. Retrieved from http://knowledge.sagepub.com.ezp01.library.qut.edu.au/view/greenfood/n12.xml Poulette, A. (2010). “Community gardens’ value”. Organic Gardening, 57(1), p. 43. Retrieved from http://search.proquest.com.ezp01.library.qut.edu.au/docview/89058924 Shisanya, S. O. (2011). "The Contribution of Community Gardens to Food Security in the Maphephetheni Uplands". Development southern Africa (Sandton, South Africa), 28 (4), p. 509. Retrieved from http://www.tandfonline.com.ezp01.library.qut.edu.au/doi/full/10.1080/0376835X.2011.605568 Spivey, A. (November 2002). Rooftop Gardens a Cool Idea. Environews Forum. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1241098/?tool=pmcentrez&rendertype=abstract

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Stauffer, J (2006) Hydroponics.Cereal Foods World, 51, 83-86. Retrieved from http://gateway.library.qut.edu.au/login?url=http://search.proquest.com.ezp01.library.qut.edu.au/docview/230389588?accountid=13380 The Aquaponic Source (2013) The Aquaponic Cycle [Image] Retrieved on 6 April 2013, from http://theaquaponicsource.com/what-is-aquaponics/ The Aquaponic Source (2013) What is Aquaponics? Retrieved on 6 April 2013, from http://theaquaponicsource.com/what-is-aquaponics/ Venkataraman, B. (2008). Country, the city version: Farms in the sky gain new interest. Retrieved from http://www.nytimes.com/2008/07/15/science/15farm.html?_r=2& Voicu, I., Been, V. (2008). “The Effects of Community Gardens on Neighbouring Property Values”. Real Estate Economics, 36(2), p. 241-283. Retrieved fromhttp://onlinelibrary.wiley.com/doi/10.1111/j.1540-6229.2008.00213.x/full World Health Organisation (1996). Food Security. Retrieved from http://www.who.int/trade/glossary/story028/en/ Zezza, A., Tasciotti, L. (2010). Urban agriculture, poverty, and food security: Empirical evidence from a sample of developing countries. Food Policy, 35, 265-273. Retrieved from www.elsevier.com/locate/foodpol

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Case study of the Brooklyn GrangeThe 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). 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).

Cyrus Dowlatshahi, http://www.inhabitat.com

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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.

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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.