Research & reports

Corina Başnou, Geovana Mercado, Åsa Ode Sang, Thomas B. Randrup, Verónica Fabio, Adrián Cabezas, Arnau Lluch, Marc Montlleó, Juan Miguel Kanai, Riccardo Saraco, Olívia Bina, Tom Wild · Nature-Based Solutions · Europe

An overview and guidance for air pollution indicators in nature-based solutions (NBS) for urban green planning and public health were provided, using three case studies in Europe and Latin America. The study noted that approaches including multidimensional indicators in research, planning, and policies are limited, and national standards for some air pollutants are missing with little evidence for health effect thresholds. Findings also indicated that knowledge of pollutant uptake in edible plants can suggest potential human exposure risks.

Mais Jafari, Rolf Morgenstern, Jonas Runte · · Germany

This chapter analyzed the co-creation pathway of Nature-based Solutions (NBS) in the Dortmund Living Lab, focusing on urban gardening, food forests, and biodiversity. It critically illustrated missing dimensions that hinder innovation, such as business opportunities, legal frameworks, and planning conditions. These identified gaps indicate challenges in governance and implementation for social innovation through NBS.

Juan Diego Torres, Sara R. Jaeger, Patricia Puerta, Amparo Tárrega · Applied Food Research · Spain

This study investigated Spanish consumers' perceptions of five lettuce cultivation systems using explicit and implicit methods with 105 participants. Local/small agriculture was most favorably regarded, while urban community gardens were perceived as less safe for lettuce production. High-tech greenhouses were considered safer but less sustainable, and vertical indoor farming elicited a surprise reaction due to low familiarity.

Grażyna Wiejak-Roy, Jaideep Roy, D. Andrew · Land Use Policy · Poland (Warsaw)

This study examined the market for allotment gardens in Warsaw, Poland, using a mixed-method approach including thematic archival analysis of regulations and hedonic regression modeling on posted offers. The findings indicate a poor transaction framework, pricing sensitive to legal and illegal private investments, and prevalent illegal rent-seeking on land. Additionally, increasing investment in allotment gardens was found to reduce biodiversity.

Dariusz Gruszka, Katarzyna Szopka, Cezary Kabała · Land · Poland (Wroclaw)

This study in Wroclaw, Poland, investigated the quality of constructed technogenic soils in urban gardens located on a reclaimed clay pit. Despite beneficial physicochemical properties and high fertility in the topsoil layers, the soils were seriously contaminated with trace elements, including zinc (up to 1700 mg kg−1), lead (920 mg kg−1), copper (740 mg kg−1), cadmium (5.1 mg kg−1), mercury (7.4 mg kg−1), and arsenic (5.1 mg kg−1). This contamination, likely from industrial and urban waste used for mine infilling, compromises soil quality and poses potential health and ecological risks.

Dennis Raphael · Policy Press eBooks · Canada; United Kingdom

This chapter documents the growth of charitable non-governmental responses to food insecurity in Canada and the UK, including food banks, food diversion schemes, and community gardens. It is shown that these responses are problematic as they fail to address the economic and political causes of food insecurity. Further failures associated with charitable responses include the experience of stigma and degradation by food bank users and the promulgation of the belief that food insecurity is being addressed.

Katja Hombrecher · Gefahrstoffe Reinhaltung der Luft · Germany

A pilot study in Germany investigated the impact of road traffic emissions on food plants grown near roads. Bioindicators like kale, chard, Lollo Rosso, and lettuce were exposed for four weeks at four roadside locations and compared to plants in a garden away from roads. While pollutant levels generally did not exceed background or EU maximum limits, significant traffic-related inputs of PAK 4, antimony, aluminum, chromium, and vanadium, and lesser inputs of copper, iron, and lead were detected compared to the control. The findings indicate a potential contamination risk for certain vegetable plants from road traffic.

Javier Rodrigo-Ilarri, Claudia P. Romero-Hernández, Sergio Salazar-Galán, María-Elena Rodrigo-Clavero · Sustainability · Spain (Valencia)

This article analyzes the impact of urban sprawl on the Valencia Plain aquifer system from 1990 to 2018 using the Weighted Environmental Index (WEI). Results show urban surfaces expanded by 70% and rainfed agricultural areas declined by over 59%, leading to a 9.2% reduction in environmental value (WEI decreased from 44.80 to 40.68). These changes threaten ecosystem sustainability and reduce the capacity to deliver ecosystem services.

Mattia Andreola · Discover Sustainability · Italy (Trento)

This study conducted three years of ethnographic research, including participant observation, in-depth interviews, and quantitative data analysis, on "NaturalMente in Trentino," a CSA initiative in Trento, Italy. The research revealed multiple lock-in points, indicating that CSA constraints stem from organizational inefficiencies, deeply rooted cultural and behavioral habits such as the use of private gardens or a preference for supermarket convenience, and rigid institutional frameworks like cooperative dominance in the local agri-food regime.

Ágnes Gagyi · Local Environment · Europe

This paper investigated urban gardening in an East European capital, focusing on institutional resources. The study found a clear relationship between a shortfall of institutional resources and the limited, conflictual promotion of urban gardens as sustainability tools. It argues that gardens' contradictions stem from the privatization of public functions, which has depleted institutions capable of implementing gardens as sustainability tools, instead outsourcing costs to garden communities.

Sara Sama Acedo, David Berná Serna, Patricia Homs Ramírez de la Piscina · Scientific Repository of Open Access of Portugal (RCAAP) · Spain (Madrid)

A study analyzed the challenge faced by community urban gardens in Madrid, Spain, in remaining transformative spaces amidst an ecossocial crisis. These gardens are initiatives situated between community and public institutional management, with their expansion and institutionalization involving practices and relationships among diverse agents. The study points out the difficulty for these gardens to maintain their transformative role—updating community ties, reciprocity, and mutual care, and reformulating relationships with "nature" in the city and food supply—without being absorbed by market logics or marginalized into welfare or community volunteering spaces.

Kirsty Lohman, Ruth Pearce · Community Development Journal · United Kingdom (Durham)

This article describes a community garden in Durham, United Kingdom, maintained by volunteers working to retain common access to green space. The garden is located on a disused bowling green, against a backdrop of a struggle over land, ownership, and community use. The council had reportedly failed to maintain the land for many years, and much of the surrounding area is owned by Durham University. The community association aims to obtain control of the land through an adverse possession claim to prevent it from being sold off by the council.

Marina Abrão Ballak Dias · Revista Andaluza de Antropología · France (Paris)

This article explored how different conceptions of human-nature relationships shaped practices in two community gardens in Paris's Goutte d’Or neighborhood. Conceptions grounded in a human–nature divide prevailed, leading to a conservationist approach. Practices stemming from this perspective were found to be in constant tension with garden goals like increasing urban biodiversity and human socialization.

Sara Sama Acedo, David Berná Serna, Patricia Homs Ramírez de la Piscina · Etnografica · Spain (Madrid)

This paper analyzes the case of community urban gardens in Madrid integrated into the Municipal Program of Community Urban Gardens. These initiatives are situated in the interstices between community management and public institutional management, generating new demands on the management of urban green commons and enabling forms of shared governance. The study reveals that these gardens face the challenge of maintaining themselves as transformative spaces without being absorbed by commercial logics or marginalized into welfare-oriented or community volunteer spaces.

Dorota Rancew-Sikora, Anna Horolets, Joanna Krukowska · Environmental Sociology · Poland

This article investigates how community gardening ideals are materialized and abandoned, applying Hannah Arendt’s distinction between types of work. Based on empirical analysis of narratives and observations in 12 gardens across Poland, the research demonstrates obstacles to democratic sustainability transitions. It proposes a processual concept of "slippage" to understand mechanisms by which departures from ideals occur in community gardens.

Sara Mahdizadeh, Yun Gao · Local Environment · United Kingdom

This qualitative study, based on 16 semi-structured interviews, examined motivations and barriers to participation in community gardens in Huddersfield, UK. Key motivations included social interaction, mental well-being, and skill development. Reported barriers were declining volunteer numbers, physical workload, limited institutional support, and accessibility challenges.

Mar Loren-Méndez, Celia Chacón-Carretón, Pablo Manuel Millán Millán · ACE Arquitectura Ciudad y Entorno · Spain (Málaga)

This study examines the urban dimension of agricultural heritage, specifically urban orchards, in cities where agrarian activity is deeply intertwined with their origin and evolution. Using Nerja, Málaga, Spain, as a case study, the research highlights that accelerated urban transformation in recent decades has led to a rupture, undermining agrarian logic by abandoning historical growth practices. The study emphasizes the fundamental role of agrarian activity in built environments and advocates for the protection of urban orchards.

Sergi Ventura, J.R. Armengol Miró, David Camacho-Caballero, Enric Casellas, Ricard Segura-Barrero, Alberto Martilli, gara villalba · Urban Climate · Spain (Barcelona)

This study used the Pseudo Global Warming method and WRF model to assess urban heat adaptation strategies in the Metropolitan Area of Barcelona. Three strategies were evaluated: increasing rooftop albedo, implementing irrigated sedum green roofs, and increasing peri-urban agriculture and urban parks. While increasing rooftop albedo provided the greatest daytime cooling (−1.75 °C), and green roofs and peri-urban agriculture showed moderate regulation, none of the strategies fully counterbalanced the projected 6 °C temperature increase by 2100, indicating a limited capacity of these adaptations under severe warming scenarios.

Izabella Pisarek, Kamila Śmieszkoł, Aleksandra Cichoń, Magdalena Śliwa, Dżoana Latała-Matysiak, Katarzyna Łuczak, Grzegorz Kusza · Journal of Ecological Engineering · Poland

A 2025 study assessed the impact of a railway line on soil quality, particularly heavy metal content, at the "Hutnik" family allotment gardens in Zawadzkie, Poland. Twenty research plots were set out near a forest complex (reference) and near railway infrastructure (a potential emission source), with soil samples collected from a depth of 0-25 cm and analyzed for total zinc (Zn), copper (Cu), lead (Pb), chromium (Cr), and nickel (Ni). Elevated concentrations of copper, zinc, and lead were found in soils close to the railway line, and based on the chemical analysis data, the study concludes that railway transport may pose a greater threat to the environment than previously expected.

Jacek Antonkiewicz, Iwona Paśmionka, Grzegorz Szychowski · Soil Science Annual · Poland

Following a flood that inundated allotment gardens in Nysa, southern Poland, for up to 14 days after the water rose on 14 September 2024, researchers analyzed 12 soil samples collected in early spring 2025 from two allotment garden sites. Most soils were found limed and disinfected, with high organic matter but low total potassium, sodium and sulfur. Zinc and copper concentrations exceeded the average for Polish arable soils, pointing to use of materials enriched with these elements.

Johanna Bock, Márcio Zamboni Neske, Martin Krauß, Andrea Dombrowski, Jörg Oehlmann · Environmental Sciences Europe · Europe

Focusing on small water bodies in private urban gardens, this study examined whether chemical pollution limits insect diversity, given that gardens make up a significant share of urban green area and can serve as important habitats and stepping stones for insects, while pesticides, fertilizers and chemical run-off from building materials can strongly affect habitat quality and insect biodiversity. Garden pond toxicity was assessed using in vitro and in vivo methods and chemical screening. Of 17 ponds examined, only one water sample and one sediment sample were found non-toxic in a bioluminescence assay with Aliivibrio fischeri. Enhanced dioxin-like activity was measured in seven water and ten sediment samples using a reporter gene assay with Saccharomyces cerevisiae, and most water extracts showed mutagenic potential in the Ames fluctuation assay (Salmonella typhimurium strains YG1041 and YG1042), while most sediment extracts were not mutagenic. Increased larval mortality of Chironomus riparius occurred in five water-sediment systems built from pond samples, correlating positively with in vitro water toxicity and with concentrations of benzothiazole derivatives measured by LC-HRMS, likely originating from EPDM rubber pond liners. Substance composition differed significantly between house and allotment gardens, with higher concentrations measured in allotment ponds. The study concludes that chemical pollution in private urban gardens may have been underestimated to date, and that pond toxicity can severely affect insect populations, warranting further study.

Finn Williams, Ruby Johnston, Aiden Campbell · International Journal of Horticulture and Food Science · Germany

At the Christchurch College of Food Technology in New Zealand, researchers compared five growing systems -- rooftop container, raised bed, peri-urban orchard, rural orchard (reference), and heated greenhouse -- for avocado (Persea americana) cv. 'Hass' under simulated Bavarian Plateau conditions, using a randomized complete block design with four replications over three years (2020-2022). The rural orchard yielded highest at 22.3 kg per tree, peri-urban raised beds achieved 18.7 kg per tree using 56% less land, and rooftop containers (200 L pots) produced only 6.8 kg per tree, confirming that container culture is viable but yield-limited; rooftop systems had the lowest weed pressure, peri-urban orchards supported the richest arthropod biodiversity, and ISSR molecular markers confirmed genetic uniformity among grafted plants across systems, ruling out somaclonal variation as a source of the yield differences.

Jarosław Chmielewski, Barbara Gworek, Alicja Walosik, Magdalena Florek-Łuszczki · Annals of Agricultural and Environmental Medicine · Poland

Soil (N=196) and root vegetable (N=94) samples from 16 allotment gardens in Warsaw, Poland, were analyzed for manganese, zinc, copper, lead and cadmium and assessed for health risk. Parsley, carrots, beetroots and celery grown in these gardens accumulated elevated levels of all five metals, and the health risk assessment found an increased risk of carcinogenic effects from cadmium and lead in consumers of these root vegetables; the authors conclude consumption of vegetables from the examined gardens should be very limited or eliminated from the diet entirely.

Ylva Wallinder · Local Environment · Europe

A study of Gothenburg, Sweden, examines the city council's shift over the past decade from associational (collective) urban gardening toward entrepreneurial gardening on municipal land, promoted through a scheme called "from garden box to hectare" that draws residents into entrepreneurial training while taking municipal gardening classes. Analyzing the consequences of this commodification of urban sustainability projects, the study finds that socio-economic resources and social relations both limit and strengthen entrepreneurial gardening practices and participants' quality of life, and that perceived competition among gardeners has turned urban gardening into a lonely, precarious, and individualized activity compared with the formalized associational gardening the municipality previously promoted. The finding points to a mismatch between the local government's sustainability visions and gardeners' actual experience.

Javier Bayo, Joaquín López-Castellanos, Marta Doval-Miñarro, Sonia Olmos · Scientific Reports · Spain

An ATR-FTIR analysis of 11 commercial compost products found microplastics in every sample, averaging 137.65 ± 6.01 items/kg dry weight and up to 631.14 mg/kg. Eco-labeled composts had significantly lower microplastic abundance, size, and concentration than non-eco products. Microplastic concentration correlated negatively with pH and nitrogen content and positively with organic matter content.