Situation analysis on urban agriculture, implemented in a variety of city around the world, identified a series of common constraints to the development of safe and sustainable urban agriculture, including:

Prohibitive urban policies and regulations

Although activities such as home-gardening and urban livestock-keeping may be well known by policymakers and planners, in many cases this knowledge does not result automatically in the recognition of urban agriculture as an important element of the city economy and land-use system. Often, urban agriculture tends to be seen as merely a ‘left-over’ of rural habits, as only temporary until the people accustom themselves to urban life, as a marginal activity with little economic importance, as a health risk and source of pollution that has to be removed, etc. Cities are often perceived as solidly built up with no area to spare. Agriculture and urbanization are viewed typically as conflicting activities that should be separated. Fear of contamination by urban agriculture and use of unclean water for food production has, over time, become institutionalized in law, and led to reluctance by many local governments and to contemplate the potential benefits of urban agriculture. In many cities, agriculture still has an “illegal� status, although it may be tolerated in practice. This however creates opportunities for local officials and policemen to levy “informal taxes�, unpredictable changes in the degree of tolerance and frequent harassment of urban farmers (many of them women). Such biases, sustained by the limited exposure of policymakers and planners to scientific information on urban agriculture and on ecological and participatory city development in general, have led to important legal restrictions on urban agriculture. Often such restrictions are among the major constraints to urban agriculture. They also prevent the integration of agriculture into urban planning as a competitive form of land use and constrain the creation of adequate support services. Creating a conducive policy environment for urban agriculture and its formal acceptance as an urban land use is one of the key issues for further development of urban agriculture.  

Limited access to productive resources and insecure land tenure

Urban agriculture is - to a large extent - being done on land that is not owned by the user: roadsides, riverbanks, along railroads, idle public lands, parks, community, institutional or public land etc. The use of such areas is, in principle, transitional and user rights are minimal. However, various systems of informal rent, lease and inheritance exist. The quality of the lands to which urban farmers do have access is often very marginal to start with. In  combination with the poverty of the majority of the urban farmers and the insecure land-tenure situation, this leads to low investments in the land, low productivity and further deterioration of the soil. Fear of eviction leads people to plant quick-yielding seasonal crops and to avoid investments in soil quality, tree and shrub components, erosion prevention, water-harvesting measures, etc.

Next to land, the access to water (especially water of good quality) and nutrients (especially manure and compost of good quality) is crucial to urban farmers, and both are difficult to obtain (although more widely available then in many rural areas). Use of water sources is often informal (e.g. tapping off wastewater disposal pipes and canals). Measures to enhance access to and security of land (and water) are crucial for urban agriculture development.

Lack of support services and appropriate technologies

Because policymakers, planners and support organization generally have little understanding of the potential of urban agriculture, urban farmers are seldom viewed as a target group for support services such as training and extension, veterinary services, technical assistance and credit services, or for supporting infrastructure such as water points and market facilities. Urban farmers especially highlight the lack of access to credit. The technologies applied by urban farmers (especially so in Africa) are normally very basic: hand labor and simple tools. Crop choices and production technologies are often not well adapted to the conditions of the production site (e.g. intensive backyard farming requires other technologies than roadside farming or production on riverbanks).

Projects oriented at technology development in urban agriculture are very scarce. There is a great need for easy-to-operate and low-cost technologies for recycling of urban biological wastes for productive use and to improve delivery of adequate support services to enhance the productivity and economic viability of urban agriculture.

Even if such support services exist, they are often oriented at larger-scale and (peri-urban) commercial farmers. The participation of often non-organised and more vulnerable groups of farmers, the urban poor, women and youth or recent migrants, in urban agriculture programme, planning and policies will need specific attention. Gender equity and social inclusion should thus be promoted. 

Potential health and environmental risks associated with urban agriculture

Urban agriculture, notwithstanding its potential for improving the environment (by using organic wastes and wastewater as a productive resource and closing the nutrient loop, by reducing the urban ecological footprint and keeping ecologically valuable areas free from construction and maintaining biodiversity in urban areas – See Module 5 &6), may also have negative health and environmental impacts. Soil erosion may occur and groundwater may be polluted if high amounts of if high amounts of fertilizers and pesticides are used in urban agriculture. If contaminated wastewater (untreated or insufficiently treated) is used for irrigation of food crops (especially green leafy vegetables) or when fresh organic wastes (not composted or not properly composted) are used as fertilizer, or hygiene is lacking in the production, processing and marketing of food (e.g. in street vending) food may become contaminated and the health of agricultural workers may be negatively affected. Cultivated areas in cities may attract or provide breeding grounds for rodents and flies and thus can contribute to the spread of diseases they carry. Certain diseases can also be transmitted to humans by livestock kept in close proximity to them, if proper precautions are not taken.

Development of safe and sustainable forms of urban agriculture should thus be promoted by taking measures to reduce the health and environmental risks associated with urban agriculture.

Before showing you how various cities have responded to these constraints, we first want to briefly discuss the various policy instruments they have available in doing so.