Hello all! I’ve been researching and writing for a few days on the topic of urban agriculture. It’s a subject that is near and dear to me, which I have spent much time studying over the past few years. I’ve taken classes on it, read a plethora of books & articles, and interned with the School Garden Project in Eugene, Oregon for the summer before entering my masters program.
This paper focuses on analysis and identification of the methods that are most suitable for urban agriculture, and it starts to envision how those methods would act and be implemented within the urban fabric. The paper is available as PDF of full text below the break.
The future of agricultural production methods and distribution is one of the most interesting issues to address within the current urban context. This is likely the case because few issues are so strongly tied to our unconscious perception of personal identity, as well as so blatantly disregarded by conventional planning and design. It was (and still is) a common perception that the future is filled with steady food supplies of every type imaginable, provided cheaply and requiring few inputs. The reality though, is that we substituted petroleum energy for human labor and created a brittle system of production, ill-suited for adapting to the changing world.
The good news about this situation though, is that we already have examples of countries that have transitioned back into sustainable agricultural practices from this type of widespread monoculture system. The most prominent of which is Cuba, which lost its petrochemical supply at the end of the cold war and was forced through this transition decades ago. Today though, we see that new smallholder systems are in place and that food security is again a reality for local residents.
“Havana currently has more than two hundred of the small urban gardens known as organoponicos. These plots yield an astonishing amount of produce- about 300,000 tons of food a year, or nearly the entire vegetable supply for the city.” (p 46, Gallagher)
Agricultural production will be forced to drastically shift its focus over the coming decades. The current environmental and economic realities no longer allow for the continuation of (materially) inefficient monocultures. Few traditional theorists see adequate solutions to this predicament, but this is the result of shortsightedness and an inability to imagine a world that is drastically different from our current one. Often, solutions are framed in terms of who we are rather than who we must become. On many checklists for healthy communities the 10 most commonly identified aspects for improvement include outdoor air quality, water supply & sanitation, housing & buildings, shops & services, food, schools & other institutions, community spaces, transport & street connectivity, communication technology, and economy & employment (p 2-3, Capon). Nearly every one of these sectors can be positively impacted by the cultivation of urban agriculture. Urban agriculture can help to improve sanitation systems, water supply and quality, pollution, crime, erosion, temperature, food security, and attractiveness, especially through dynamic planning in which location and cohabitation of agricultural production evolves with the city due to its relatively temporary and transient nature (p 12, Mougeot 2005). We can see that the non-primary benefits of urban agriculture cover a broad range of services that are currently provided through individual programs.
In the example of food security Mugeot has found that “UA is a critical supplier of certain types of foods that tend to be rich in micronutrients, such as fresh greens and vegetables. Thus, self-provisioning – growing even a small amount of food for home consumption – is a very important strategy for many poor and middle-income households” (p 59, Mougeot 2006). For many households the availability of quality produce may mean the difference between needing food assistance or not, and providing spaces within the urban fabric to undertake these types of subsistence activities will likely benefit the government through reduced assistance payments.
In another example we can see that urban agricultural activities help add value to the city by solidifying local identity and increasing the stability of the tax base. Mugeot goes so far to state that urban agriculture will be one of the major forces in responding to globalism
“An unprecedented concentration of people from widely diverse origins is creating a mosaic of food cultures never seen before, in any given city today, anywhere in the world…. these products could enable more people to reassert their local territorial identity and communal cultures (in the face of global trends).” (p 276, Mougeot 2005)
In response to these existing conditions and currently popular perceptions, I find it necessary to propose a new way of looking at the culture and distribution of agriculture. As Mugeot says in conclusion to his examination of the social and political aspects of urban agriculture “for agricultural officials UA usually refers to food production and they stress generally its food security rather than greening effects… worrying less about their interaction with surrounding land-uses and activities, and in cities such interactions are critical, which is why UA cannot be left to Ministry of Agriculture professionals alone” (p 273, Mougeot 2005). Many elements of this thesis have been proposed loosely, said weakly, or examined individually, but I have never seen them synthesized and organized into a unified thesis regarding the cultural impacts, methods, and implementation of urban agriculture practices from an architectural perspective.
After examination of many current materials regarding the production of urban agriculture, and based on extensive previous study of agricultural systems, I have concluded that future agricultural production will be based on a dichotomous approach (Stangl).
One essential aspect of production systems will be the facilitation of low-input perennial foraging systems. These will include the improved management and rehabilitation of wild fisheries and game preserves, the installation of edible urban landscaping (such as the Beacon Food Forest), and the cultivation of semi-wild grassland production a la Wes Jackson. Though it is impossible for these types of systems to produce the majority of our agricultural needs, they require few energy inputs to maintain and have the benefit of improving other ecosystems services.
The other essential aspect of agricultural production systems will come in the form of high-input intensive annual cultivation. These systems will be high-yielding (with production of up to 18 tons/hectare annually) and space efficient, but will require hand management and cultivation (Kumar et al). These systems will include greenwalls, community gardens, and rooftop farming. The mixture of these seemingly opposing approaches will enable a (culturally) necessary reconnection with our food systems, the drastic reduction of petroleum and mechanical inputs (from both production and transportation), and the improvement of necessary ecosystem services.
In this examination I will focus on the aspects of these production systems that can be most readily integrated into our urban fabric with an emphasis on high-density applications. For more information on the production systems outlined above that are more readily applied to suburban, exurban, and rural areas I recommend further study of Wes Jackson, Joel Salatin, the reintroduction of Bison on the American prairie, and the University of Oregon Urban Farm program.
Basic definitions of the various types of urban agriculture are outlined in the following section and the ones most suited for widespread implementation are identified for further discussion in the following section. Methods deemed unsuitable for widespread implementation are examined in detail here, since they even though they lack the necessary requirements my conception of urban agriculture they are still valuable for suburban and rural agricultural production.
Aquaculture is the farming of water-based edibles such as plants, mollusks, and fish. In the form of constructed ponds it can integrate well into the other urban agriculture systems, the urban fabric, and building environmental systems. It provides nutrients for crops, necessary irrigation, and a supplemental food sources if stocked with fast growing carp or tilapia. Water features help to beautify public areas and are always pleasant to gather near. The ponds can provide a catchment basin for rainwater and assist with the creation of a cooling breeze. Aquaculture can be wasteful if created alone in dry climates like San Diego, but should be integrated into other urban agriculture systems as often as possible.
Recent developments in saltwater crops have led an increase in the amount of arable land that is available for agricultural production, especially in urban areas in conjunction with the rehabilitation of tidal marshland native habitats. Staple crops currently available for this type of production include rice and tuber crops. These methods of production are especially beneficial because they require limited use of freshwater resources and if properly located, use tidal fluctuations for ebb and flow flooding irrigation. Additionally, they can provide a buffer zone to manage traffic in sensitive habitat areas. Although these methods are beneficial, their use is limited to specific instances where water movement has already been calmed by sandbars or other partially submerged landscape features and oceanfront property used faces an undredged bay. Due to these limitations saltwater crops have limited use in urban agriculture and further exploration of the topic will be reserved for future projects that deal with these specific types of environmental conditions.
Several examples of underground farming have recently been built and are widely lauded as successes, but ultimately none have been in operation long enough for an accurate examination of their benefits and pitfalls. Often these systems are built in existing warehouses or basements using hydroponics and fluorescent lighting. These systems utilize ebb and flow, thin film nutrient, static airstone, or misting methods of irrigation: requiring the purchase and maintenance of a variety of pumps, valves, timers, and air compressors. Additionally, the use of fluorescent lighting means that large plants can’t be effectively grown due to the exponential degradation of lumen availability at a distance from the lights to the plants. These factors combine to limit this type of agricultural production to mainly fast growing leafy vegetables such as lettuce, spinach, and basil. Due to the high energy and equipment costs, as well as the limited types of production, these have limited use and should only be considered to supplement production after other available methods have been put in place.
Of the methods examined, a few are particularly suitable for integration into the urban fabric. Methods that were excluded from this section have applications that are either too specific (in the case of saltwater agriculture as a buffer for tidal marshland restoration) or require too much energy input (in the case of underground agriculture) to be useful for the current focused discussion. Within this section I will examine in greater detail the methods that I have deemed best suited for urban agriculture. Though much of the selection process was based on the criteria of increasing density and ability to integrate with the existing built environment, scale is also a major factor. Energy and economic costs to create large scale urban agricultural production is excessive; solutions utilizing many smaller scaled interventions can strike a better balance between sufficiency and practicality (Sorhin).
Vertical farming is most ideally suited for application in high-density urban centers. Vertical gardens use either a continuous structural facade system that stands independently of existing buildings, or a modular box system that can cover the wall of an existing building working much like a series of pots hung from the structure. Irrigation is usually targeted drip irrigation to save water. A variety of growing substrates are used (p 9, Weinmaster).
A great example of this method can be seen in a new vertical garden in the town square of San Vincente del Raspeig. The structure is a freestanding metal frame skinned with a metal mesh, plants are grown in a felt media sandwiched in the center and maintenance is accessed through a suspended scaffold system. The garden helps to provide shade, allows for the inclusion of a park within the existing plaza without detrimentally impacting the character of either element, and helps to visually separate two buildings that sit near the edge of the square (Meinhold).
Greenwalls featuring edible plantings are limited to the first few stories on the exterior envelope of tall buildings unless accompanied by moveable service infrastructure for harvest and maintenance. In this case access will have to be limited to service personnel only and harvest will be most appropriate for sale by a private entity (ideally providing a supplemental income for the building owner). If greenwalls are used as part of a dual envelope system as the interior skin, residents of the building can mostly undertake harvest and maintenance and the property owner can ask for higher rent due to increased well being of occupants.
Green roofs and vertical gardens are both extremely useful for inclusion in dense urban settings because they can play a large part (up to 30% reduction of cooling costs) in reducing the urban heat island effect, making cities more comfortable and efficient places to live (p 12, Weinmaster). Additionally, they can have a positive effect on storm water management, biodiversity & conservation, indoor air quality, indoor acoustics, and the health & wellness of residents.
Rooftop farming is the method most commonly associated with urban agriculture, but it is also the most problematic. It utilizes previously wasted space, beautifies the city from an aerial perspective, and is the first stop for reducing runoff to storm drains. However, the installation of a green roof can add between 14 and 199 pounds per square foot of dead load (p 10, Grant). Due to this additional load structural systems often have to be retrofitted or rebuilt, drainage systems redesigned, and roofing systems upgraded to eliminate ponding and other water collection issues (Oberndorfer). Despite these disadvantages, building owners in Chicago have seen significant benefits from the installation of rooftop native gardens. In this case the lack of agricultural production makes sense because the buildings retrofitted consisted of mainly office space, providing no specific stakeholder for the maintenance and harvesting of agricultural production. However, in Singapore, researchers estimated that there were more than 600 hectares of usable space available on rooftops which would likely yield 122,000 tons of produce annually, supplying approximately 30% of local vegetable consumption (p 3, Capon).
So despite a lack of widespread implementation thus far, the possibility exists for new types of farms occupying our rooftop spaces. Researchers in Arkansas found that “Variety in the plant palette will foster greater biodiversity in the green roof system… the combination of these species promotes green roof coverage across the growing season, thereby increasing biodiversity and seasonal interest… plants are not only an important part of the green roof functionally through storm water interception and evapotranspiration, but these plants also create scenery, wildlife habitat, and an overall healthy environment” (p 13, Toland et al). Since small farms with a high diversity of products will be most desirable to implement, this suggests two possible models.
Buildings that include a large market or several full-service restaurants would be ideal places for rooftop agricultural production. The businesses could either expand their business structure vertically to directly undertake production themselves and have further control over the supply chain, or they could establish a symbiotic relationship with another business created to specifically manage rooftop production and distribute to in-building customers. In either case this method of production would be best suited for mid-rise to high-rise buildings primarily occupied by commercial spaces, with ownership and distribution of produced crops being both owned and distributed privately.
The second type of building ideal for rooftop agriculture is the low-rise to mid-rise building primarily occupied by residential units. In this case ownership and distribution of produced crops can be managed through private or cooperative ownership, depending on the desired form of residential community. This type of rooftop agriculture is analogous to other community garden arrangements, and best discussed under that heading along with ground level gardening.
Community gardens are a large and well-established part of any urban agriculture system. As previously discussed, these can occupy the rooftop of residential buildings or as is more commonly seen, empty lots for temporary infill. Wherever they exist, they provide a myriad of services including the facilitation of increased community cohesiveness, a reconnection of urban residents to their rural roots and the food production systems, and a sense of recaptured control over the availability and sources of daily caloric intake.
In addition to these communal services, the creation of community gardens can also benefit the city government directly. This can take the form of financial compensation as discussed by Gallagher when talking about the Pinegree Potato Patch “Nearly 1000 families participated in the first year, farming on some 430 acres of loaned land… what the families didn’t eat was sold as surplus and the whole operation reaped 4 times as much money as it cost to set it up” (p 42, Gallagher). It can also take the form of the temporary occupation of abandoned lots by urban agriculture resulting in reduced costs for patrolling and maintaining the property (p 64, Mougeot 2006). Economic benefits can also include cost savings to waste management due to reduced landfill use, cost savings on brownfield cleanup from vegetative remediation, reduced need for storm water infrastructure and management due to better water retention in soils, and improved health and labor productivity due to better air quality (p 73, Viljoen & Bohn).
Depending on their conceptualization, community gardens can take on a wide variety of structural organizations and formal goals. They are most commonly conceived of as either lease gardening (in which plots are individually worked and owned) or co-operative gardening (in which everyone contributes to cultivation of a larger, interconnected plot). Although lease gardening is predominant in the United States, it has little hope for creating significant impact on the agricultural landscape. While many say they would like to undertake gardening “a rule of thumb is garden plots should be provided for 30-50 percent of the population in a high density residential area” (p 135, De La Salle & Holland).
The co-op model is more realistic and suited to taking advantage of the urban scale and resources. Viljoen and Bohn say it best:
“Smaller producers, as we note elsewhere, can respond better to changes in consumers’ taste, specialize in high value products, and have less need for wage labour, and expensive capital and infrastructure. Farmer co-operatives can benefit from organizational economies of scale and conduct activities which the individual would find hard to achieve in isolation. Marketing, financing, and technical assistance can be provided through this co-operation. It can also ensure the farmer or enterprise has an almost guaranteed market for the produce within certain quality standards.” (p 70, Viljoen & Bohn)
A good example of this type of co-op gardening and the types of government facilitation that can help is uncovered in an examination of Cuban food shortages during the 1990’s. Empty urban lots and open areas like yards were transformed into gardens and farms at an incredibly rapid pace and the government facilitated these efforts by “making it free to adapt unused, public land into food production plots… trained a network of extension agents… created “seed houses”… (and) established an infrastructure of direct-sale Farmers’ Markets (Quirk). Such farming efforts will ultimately be the basis of expansions in urban agriculture – functioning as the centers of concentrated food production, distribution, and culture.
In terms of food security and the creation of a continual fabric for the urban agricultural system, edible landscaping is the most effective method. “Greenways and transit corridors can offer community garden spaces in urban areas. Agreements and liability will need to be addressed with the corridor owners, but linear gardens can offer a great value, keep crime down, reduce unwanted garbage disposal, and make a transit corridor a seam that joins a community rather than a fence that divides it” (p 132, De La Salle & Holland). Edible landscaping is also useful for producing and distributing food using a scattered low-input agricultural system that encourages placemaking through the continual use of human scale interventions. “It is the layering of systems and programming, based on a fundamentally human-scaled relationship with productive landscapes, that affords AU such tremendous opportunities for placemaking, perhaps tangible and enduring form of sustainable design” (p 118, De La Salle & Holland).
The public nature of these projects necessitates distribution of the resulting product primarily through foraging and individual collection. This doesn’t preclude the possibility of agricultural sales to recoup maintenance and installation costs, but it does mean that production can be neither guaranteed nor centrally harvested. What this method lacks in practical application for large-scale production and distribution, it makes up for by supplementing food security for the most vulnerable groups in the urban population. Ultimately, most of the yield from this method of production would be foraged by local and transient residents or eaten by animals. While this method of distribution may seem somewhat unrealistic it has been productive in past cases, most notably in Portland, Oregon. “In 2007 alone, volunteers associated with the Portland Fruit Tree Project in Oregon harvested 3,400 pounds of fruit for food banks” (p 98, De La Salle & Holland). This type of urban foraging is made more efficient through the use of modern technology, with open-source mapping websites like fallingfruit.org playing a crucial role in ensuring access to and tracking of urban edibles (fallingfruit.org).
More centralized and organized projects have recently been undertaken with great success, the most notable of which is the creation of the Beacon Food Forest in Seattle, Washington. The food forest uses a concentrated gardening technique with three layers of plantings to enable the growth of edibles, natural habitat restoration, and the creation of public greenspace in a single area. The upper level consists of fruit and nut trees with berry shrubs, perennials, and annuals constituting the lower layers (beaconfoodforest.org). The food forest is located on land owned by Seattle Public Utilities that houses the city water reservoir, so stewardship of the area is one of the major beneficial synergies of the project (beaconfoodforest.org).
Although there are many methods of implementing urban agriculture and its application will always be necessarily specific to the context, the use of vertical gardens, rooftop gardens, community gardens, and edible landscaping as I outlined above will be crucial in any proposal. These elements will require integration into the urban landscape and careful planning to achieve the goal of being a single, interconnected system that layers onto the existing cityscape. To do this will require the use of concepts from many fields including permaculture, architecture, planning, and conservation development.
I have already touched on the importance of other aspects and so I will say only this about conservation development. The preservation and rehabilitation of land must be done within current economic and social realities if we hope to make any real progress within the coming decades. Although regulatory mandates often produce results, a readjustment of subsidies to reflect the true costs and values of our current lifestyle is likely more helpful. But even without these changes, market forces will drive the construction and renovation of buildings that are more efficient and environmentally friendly (Sentman). This is the area in which conservation development is strongest because it finds ways to incorporate preservation with economic development, through voluntary participation (McMahon). This approach is the key to any solutions that will be broadly acceptable enough to have a significant impact.
If urban agriculture is to flourish as one of the elements that will create the classic cities of tomorrow, it will need the persistent backing of planning and design professionals. They will need to push from all directions to rebuild the interconnected systems that have been systematically destroyed over the last century. I was once told that our cities had lost their magic because grand visions no longer existed. People stopped dreaming them when disillusioned by past failure and stopped fighting for them when worn down by bureaucracy. This is one piece of my grand vision: that of a world made whole through a reassessment and reconnection of its parts, of a landscape that embraces the totality of our collective being through beauty and fierce authenticity. This vision is what makes me push myself daily and hopefully will help to inspire others.
Along with this desire, a plan is necessary and I have started to outline one below. These checklists summarize the most important takeaways gleaned from my research, from a policy and design standpoint. Although there are innumerable context specific details regarding the implementation of these methods and the addition of others, which are unlisted, these actions and considerations should be widely applicable in most scenarios.
Planning and Permitting Modifications
- Replace streetscape and park trees with edible bearing trees as landscaping schedule identifies marks existing plantings for removal.
- Survey existing buildings for ability to retrofit with rooftop gardens and require that new construction three stories and over includes a rooftop native or perennial edible garden.
- Create temporary use permits to allow urban agriculture activities on vacant lots not currently undergoing development.
- Require the installation of perennial edible landscaping in all government projects.
- Rezone coastal areas to allow for the regulated cultivation of saltwater crops immediately inland of habitat restoration zones.
- Examine and modify zoning regulations regarding poultry, livestock, and farming within the city.
Urban Agriculture Integration Checklist for Designers
- Consider the occupants of any designed structure and include either a native or perennial edible garden on the roof, with special consideration towards whether produce will be foraged or harvested.
- Consider how adjacent lots will be impacted by plantings and try to find symbiotic opportunities for designs.
- Where appropriate, substitute shading devices for greenwalls, look especially for plants with large amounts of leaf movement to improve solar gain.
- Look for opportunities to integrate rainwater catchment, aquaculture, landscaping irrigation, and if possible greywater filtration into attractive and temperature controlling design features.
- Plan for the preservation of existing community gardens through designs for new construction.
- Attend community garden planning sessions to help locate temporary and permanent elements in configurations that might best allow for preservation.
- Plan for the integration of compost material storage and processing on-site including the incorporation of city collected waste material, with an eye towards integrating building heating systems.
- Integrate pollinator attractors or beekeeping areas into designs with a special focus on maintaining the safety of residents.
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