Urban agriculture is a dynamic concept, given the wide range of urban situations and stakeholders. This diversity is one of its main attributes. Urban farming systems are in constant development as urban farmers adapt their existing practices or come up with new ones. Innovation is continuously taking place. Previous UA-Magazines have looked at its multiple functions, its role in community building, experiences with policy development for urban agriculture and support to urban farmer organisations. Taking this line further, this issue looks at how urban farmers can be supported in their efforts to improve their livelihoods. As in rural areas, farmers in cities are constantly adapting to changing circumstances and are experimenting and innovating on their own. This issue of the UA-Magazine takes stock of a broad range of experiences related to innovation by urban farmers and the efforts of other actors to support the farmers’ initiatives. It explains concepts and gives examples of farmers’ innovation and how it is being stimulated. Contributions are on technical innovations in vegetable farming for confined spaces, in water use, in livestock production, and in waste recycling, but also on social innovation as in community based agriculture or innovation in marketing and entrepreneurial agriculture. These experiences show that technical innovations often have to go together with organisational or institutional innovations. Special emphasis in this issue is given to the use of participatory methodologies for promoting innovation in urban farming systems.

This issue of Urban Agriculture Magazine is a collaborative effort of the RUAF Cities Farming for the Future Programme; PROLINNOVA (Promoting Local Innovation), an international learning and advocacy network that currently involves governmental and non-governmental organisations in 16 countries in Africa, Asia and Latin America on promoting local innovation in ecologically-oriented agriculture and natural resource management (www.prolinnova.net); and Urban Harvest, a system-wide initiative of the Consultative Group of International Agricultural Research (CGIAR) to direct and coordinate the collective knowledge and technologies of the Future Harvest Centres towards strengthening urban and periurban agriculture (http://www.cipotato.org/urbanharvest/home.htm).

The issue starts with two articles that systematise rural and urban experiences in enhancing local innovation processes. In the first introductory article, Will Critchley, Chesha Wettasinha and Ann Waters-Bayer present lessons learnt in a series of programmes that sought to scale up and institutionalise participatory approaches to innovation development in agriculture and natural resource management. The second introductory article, by Henk de Zeeuw and Gordon Prain discusses how specific urban conditions influence the process of innovation in urban farming. The urban setting, the authors argue, offers numerous opportunities and challenges for technical, organisational and institutional innovation. Following these two introductory articles, this issue presents 19 case studies on agricultural innovation in cities around the world. Together, these articles cover a wide spectrum of experiences from a total of 18 countries in the North and the South.

We would appreciate your comments on the articles in this issue and welcome further reports on your own experiences in stimulating innovation in urban agriculture.