Co-benefits vary depending on the type of project implemented. Generally, the more inclusively a specific solution is planned and developed (via participatory processes such as co-development and co-creation involving local communities), the more co-benefits are generated. 

Aesthetics, Mental wellbeing/quality of life, and Social equality and justice, Social cohesion: Community gardens contribute to developing a sense of place in citizens, also deepening their connections to nature, finding stress release and recreating a strong relation with the way food is produced. For instance, in Barcelona, stress release, social cohesion and integration have been considered by users among the most valued ecosystem services provided by urban gardens. Also, in the same case study, most of the beneficiaries were older, low-middle income, and migrant people, thus demonstrating that if properly distributed, designed and assigned, community gardens can support social equity and justice in cities, offering benefits to all, including the more vulnerable groups of citizens [5]. 

Sustainable and resilient food systems, Boost local business, Proximity economy: Urban gardening contributes to producing local food. It also has potential to boost organic production, for example, by introducing criteria of organic production in the definition of the terms of conditions to allocate spaces. According to a study to evaluate the potential of urban rooftop gardening in Bologna, it was estimated that it could provide more than 12,000 t year−1 vegetables to Bologna, satisfying 77 % of the inhabitants’ requirements and supporting food security in the future [6]. At the same time, boosting local production and proximity economy could contribute to the creation of a resilient urban environment and facilitate a city’s recovery when faced with a sudden crisis. 

Enhanced citizen participation, connectivity, and community life: As co-managed spaces, community gardens can support citizens’ participation and community life, also establishing inter-generational relations and supporting the meeting of diverse communities. This may result in mixed governance models, including bottom-up processes that boost the social benefits of gardening such as development of social capital, neighbourhood participation and community sharing [7]. 

Physical health, Healthier and more attractive lifestyles: Community gardens can help in supporting a more active and healthy lifestyle, attracting people to spend more time in the green, and also involving physical activity in the food production. Specifically, community gardens may be one form of green space capable of increasing physical activity for demographic groups not typically catered for by standardized park design, such as older people [8]. 

Species increase, Biodiversity conservation, Pollinators increase: Community and allotment gardens can enhance species diversity in vegetable gardens and could, if properly planned, also provide significant opportunities for pollinators increase in urban areas as researchers acknowledged in a study of 360 sites in four UK cities [9]. 

Pollinator verges and spaces 

Green filter area 

Urban garden bio-filter 

Pollinator verges and spaces 

Circularity food cities 

Food and nutrients recycling 

Community composting 

Urban form and layout: 

For community and allotment gardens, there should be sufficient land within urban areas. As in the ProGIreg project, post-industrial, abandoned and vacant land could be considered a great resource for community-based urban farms and gardens, after proper control of land and water quality. Floating gardens require blue infrastructure in the city (river, lakes, canals).  

Policy and regulatory/legal framework: 

At EU level, within the overall framework of the EU Green Deal: 

• The European Biodiversity strategies: cities with a population more than 20,000 are called upon ‘to develop Urban Greening Plans, including measures to create biodiverse and green urban forests, parks and gardens; urban farms; green roofs and walls; tree-lined streets; urban meadows; and urban hedges. To facilitate this work, the Commission set up an EU Urban Greening Platform with cities and mayors in 2021 under the ‘Green City Accord’ [14]. 

• The Milan Urban Food Policy Pact is a city-driven initiative developed to support food production in urban areas [15]. 

At local level, cities may refer to diverse strategies and laws: 

• Urban agriculture regulations and codes, including in relation to production and sale of products. 

• Floating gardens are still quite a new concept and no specific policies for their promotion were found. 

Funding and financing: 

The financial governance of community gardens could assume various forms, for example, renting allotment places or assigning them to local association and civil society groups.  

The criteria set to allocate spaces can greatly contribute to making a more inclusive and sustainable use of the space (e.g., using criteria for organic production, for specific groups to be involved, residence in a specific geographic region, payment of dues). Criteria could also include the possibility of selling products thus creating sustainable local businesses. According to an analysis of more than 100 case studies of urban agriculture enterprises, urban farmers are the prototype of professional entrepreneurs, adapting their business to market demands and seeing proximity to the city more as an opportunity than a threat (Urban Agriculture Europe project, COST Action, reported in [10] [12]). 

Project governance and implementation modalities: 

In the context of urban densification and lack of open spaces in central urban areas, new forms of small-scale urban gardening practices have emerged. These practices respond to urban pressures and open new modes of green space governance, presenting alternative and multifunctional ways to manage and revitalise cities. Many forms of bottom up and top down collaboration exist and, as detailed in the context of urban gardening practices in Geneva [11], there are several emerging forms of collaboration, partnerships, and governance patterns that involve public and private sectors and increase participation by civil society actors. An interesting case is the project SeedCity grows! In which ETH Zurich planned to create a closed-loop system of local vegetable gardens with composted waste from the campus, maintained by a volunteer association of students and staff. It also aimed to establish a vegetable delivery scheme with organic producers in the region [4]. 

Technical/infrastructure:  

When defining the place for a new community, floating or allotment gardens, soil composition and nutrient values of the soil should be analysed to understand production potential and ensure safety. Also for sustainability of the project, proper consideration should be given to water source for irrigation, including to water saving and reuse, whenever possible. 

Urban form and layout:  

The precariousness of land access for urban agriculture is an important limitation, particularly for disadvantaged communities [13].  

Policy and regulatory/legal framework: 

Pressure on land and potential implications this has for spatial planning and the protection of open spaces, also in case of unsustainable food production [10]. Planners have begun to pay attention to urban agriculture but should more explicitly support the goals of food justice in their urban agriculture policies and programs [13]. 

Project governance and implementation modalities: 

Urban farmers may be lacking in experience and specific skills in areas such entrepreneurship, networking and/or technical skills to produce quality food [10]. 

Literature  

[1] United Nations, Department of Economic and Social Affairs, Population Division. 2019. World Urbanization 

Prospects: The 2018 Revision (ST/ESA/SER.A/420). New York: United Nations. https://www.un.org/development/desa/en/news/population/2018-revision-of-world-urbanization-prospects.html.   

[2] Cepic et al. 2017. Urban Community and allotment gardens: research trends and look ahead. Agriculture & Forestry, Vol. 63 Issue 4: 191-200, 2017, Podgorica. DOI:10.17707/AgricultForest.63.4.20.  

[3] Benis and Ferrao, 2017. Potential mitigation of the environmental impacts of food systems through urban and peri-urban agriculture (UPA) – a life cycle assessment approach. Journal of Cleaner Production Volume 140, Part 2, 1 January 2017, Pages 784-795. https://doi.org/10.1016/j.jclepro.2016.05.176. 

[4] Curran. M. et al. SeedCity grows! - A community garden initiative for local waste recycling, food production and biodiversity conservation in Science City, ETH Hönggerberg (n.d.). http://www.sfe.ethz.ch/files/05%20Erfa%204%20-%20Land-%20und%20Waldwirtschaft/03%20Literatur%20zum%20Thema/Proposa_SeedCity.pdf. 

[5] Camps-Calvet et al. 2016. Ecosystem services provided by urban gardens in Barcelona, Spain: Insights for policy and planning. Environmental Science & Policy. Volume 62, August 2016, Pages 14-23. https://doi.org/10.1016/j.envsci.2016.01.007.  

[6] Orsini, F. et al. 2014. Exploring the production capacity of rooftop gardens (RTGs) in urban agriculture: the potential impact on food and nutrition security, biodiversity and other ecosystem services in the city of Bologna. Food Sec. 6, 781–792 (2014). https://doi.org/10.1007/s12571-014-0389-6. 

[7] Burt, K. G., et al. 2021. A systematic, mixed studies review of the outcomes of community garden participation related to food justice. Local Environment, 26:1, 17-42, https://doi.org/10.1080/13549839.2020.1861589. 

[8] Middle I. et al. 2014. Integrating community gardens into public parks: An innovative approach for providing ecosystem services in urban areas. Urban Forestry & Urban Greening. Volume 13, Issue 4, 2014, Pages 638-645. https://doi.org/10.1016/j.ufug.2014.09.001. 

[9] Tew, N.E., et al. 2021. Quantifying nectar production by flowering plants in urban and rural landscapes. Journal of Ecology, Volume 109, 1747–1757, https://doi.org/10.1111/1365-2745.13598. 

[10] EU Parliament, 2017. Urban agriculture in Europe : Patterns, challenges and policies. James McEldowney, Members' Research Service, December 2017 — PE 614.641. https://www.europarl.europa.eu/thinktank/en/document/EPRS_IDA(2017)614641.  

[11] Nikolaïdou, S. et al. 2016. Urban Gardening and Green Space Governance: Towards New Collaborative Planning Practices. Urban Planning, Volume 1, Issue 1, Pages 5-19. https://doi.org/10.17645/up.v1i1.520.  

[12] F. Lohrberg, L. Lička, L. Scazzosi, A. Timp (eds.). 2015, Urban Agriculture Europe, Jovis. 

https://www.ideabooks.it/wp-content/uploads/2016/12/Urban-Agriculture-Europe.pdf.  

[13] Horst, M. et al. 2017. The Intersection of Planning, Urban Agriculture, and Food Justice: A Review of the Literature, Journal of the American Planning Association, 83:3, 277-295, https://doi.org/10.1080/01944363.2017.1322914  

Websites 

[14] European Commission, The Green City Accord, https://environment.ec.europa.eu/topics/urban-environment/green-city-accord_en. 

[15] Milan Urban Food Policy Pact, https://www.milanurbanfoodpolicypact.org/. 

Allotments, community gardens and floating systems can contribute to greenhouse gas emission reduction thanks to carbon storage and sequestration processes during plant growth cycles.  

Urban food production is important for climate neutrality and circular economy processes. Producing food closer to or within urban areas can greatly contribute to diminishing CO2 emissions related to food transport and logistics. As estimated in the city of Lisbon, eliminating losses and wastage in the supply chain could reduce Global Warning Potential (GWP) by 8.2% and producing food within the borders of Lisbon could further reduce GWP by 2.6% [3]. 

It would also contribute, for example, to re-using organic waste as compost for vegetable gardens and support a transition towards a circular model. For example, the community garden initiative at ETH Zurich will create a closed-loop system of local vegetable gardens of rare and endangered crop varieties fed with composted waste from the campus [4]. 

Public Private Partnerships 

Integrated land use and urban planning 

Land use planning regulation 

Geospatial information 

GHG scenario modelling  

LCA/LCC 

Urban metabolism mapping 

Projects (case studies) 

URBAN GreenUP aims at the development, application and replication of renaturing urban plans in a number of European and non-European partner cities to mitigate the effects of climate change, improve air quality and temperature, manage water, as well as to increase the sustainability and liveability of cities through innovative nature-based solutions.  Part of the project is the creation of green fences, mobile vertical green gardens and hydroponic green facades. The project has been implemented in Izmir (Turkey), Liverpool (UK), Valladolid (Spain), Chengdu (China), Ludwigsburg (Germany), Mantova (Italy), Medellin (Colombia) and Quy Nhon (Vietnam), and involves a number of other cities in its activities. Specifically, Liverpool developed floating gardens, calling them ‘Green Islands’ (H2020, 2017-2022). 

ProGIreg uses nature for urban regeneration, mostly of industrial and post-industrial areas, with and for citizens. The project includes three European frontrunners cities, Dortmund (Germany), Turin (Italy) and Zagreb (Croatia), as well as Ningbo (China), that host Living Labs in post-industrial districts where nature-based solutions, including community-based urban farms and garden are developed, tested and implemented. Moreover, four other cities are following the process to further uptake solutions: Cascais (Portugal), Cluj-Napoca (Romania), Piraeus (Greece) and Zenica (Bosnia and Herzegovina) (H2020 project, 2018-2023). 

NATURVATION seeks to develop understanding of the potential of nature-based solutions in cities. Among other activities, the project created an Urban Nature Atlas, a comprehensive database of nature-based solutions for cities. The atlas is based on a systematic survey of NBS interventions in 100 European cities, among them the Telheiras allotment garden in Lisbon (H2020 project, 2017-2022).