Research & reports

Anne-Kristin Løes, Sebastian Eiter, Tatiana Rittl · Environmental Sciences Europe · Europe

Using soil data from ten peri-urban case farms near Oslo and Bergen, Norway, this study estimated how quickly potentially toxic element (PTE) concentrations would rise in soil under intensive application of compost or digestate from food waste, composted garden waste, or horse and poultry manure applied annually to meet a theoretical carrot crop's nitrogen, phosphorus and potassium demand. Under this intensive fertilization scenario, Norwegian soil quality limits for PTEs would be reached within 20-85 years, faster in soils with more organic matter, with limits reached first for copper and zinc, both essential micronutrients. The urban waste-based fertilizers were also found to be poorly balanced in macronutrients, with rates covering potassium demand leading to high phosphorus and nitrogen surpluses. The study concludes Norway's PTE regulations are stricter than the EU's and do not support recycling organic matter and nutrients from urban waste.

AZOLLA Projects · Open MIND · Europe

This document, prepared under Activity 2.1 of the Carbon Farming MED project, defines the criteria for selecting pilot farms for a carbon-farming program across two Mediterranean regions, Italy and Spain. Farms practicing regenerative agriculture or agroforestry were required to meet mandatory conditions — legal compliance, access to internet and car transport, and the economic capacity to dedicate 0.5 ha to the study — plus preferable conditions such as soil free of heavy-metal contamination, historical soil analysis data, pollinator habitat and biological corridors, efficient water management, participation in farmers' markets or community-supported agriculture, a track record with circular-economy practices, and potential for scaling. Three farms in Catalonia and three farms in Spain were selected, with primary activities of viticulture, olive growing, horticulture, and agroforestry; on-farm data will be collected from these farms to monitor and validate soil organic carbon (SOC) content.

Matthias Middendorf, Marius Rommel · Frontiers in Sustainable Food Systems · Germany

This study used a transdisciplinary mixed-methods approach, combining literature, qualitative and quantitative data, in cooperation with the German CSA Network to build a framework capturing the diversity of Community Supported Agriculture (CSA) in Germany, where CSAs grew from about 10 to over 500 in just over a decade yet remain niche. Using the framework to co-develop a survey covering 70 participating CSAs, the researchers found that community financing (domain A) is the defining characteristic distinguishing CSA from other alternative food network forms, and confirmed high diversity in differentiating characteristics (domain B), including governance types split among producer-led, consumer-led and integrated CSAs.

Adriana Díaz Caamaño · Academia XXII · Spain

This essay frames urban food cultivation and harvesting, once a common practice around human settlements in past centuries, as a new trend for urban sustainability amid an environmental crisis driven by city growth and its planetary impact. It argues that unsustainable agriculture is straining to feed a vast population with little awareness of the countryside or of its benefits for mental and physical well-being, but presents no specific study data or case findings.

David Berná Serna, Sara Sama Acedo, Patricia Homs Ramírez de la Piscina · Revista Española de Sociología · Spain

Against the backdrop of the current eco-social crisis, this article analyzes the "eco-transformative capacity" of collective initiatives in three Spanish case studies: neo-ruralization and natural wine production in the Sierra Oeste de Madrid and southern Sierra de Gredos, agroecological supply systems in Catalonia, and community urban gardens integrated into a municipal program in Madrid. The analysis focuses on the motivations, challenges, and limitations agents encounter while practicing sustainable ways of dwelling, producing, and consuming, and on their relationship to public institutional agendas on eco-social transition.

Ada Baldi, Nicolas Lucio Gallo, Anna Lenzi · Renewable Agriculture and Food Systems · Italy

Semi-structured interviews with participants in the "social gardens" of Prato, Italy — plots the municipality assigns to individual pensioners or unemployed people for growing vegetables for home consumption — examined demographic and socio-economic characteristics, cultivated crops, and plot areas. The typical gardener was male, retired, averaged 74 years old, and had a low level of education. A 50 m2 plot with 40% of its area cultivated was estimated to yield about 90 kg of vegetables per year, roughly 61.5% of one person's fruit and vegetable needs. Tomatoes occupied more than 80% of the cultivated area. Vitamin C and Vitamin A showed the highest nutrient contributions, while calcium and sodium showed the lowest.

Francisco Tomatis, Monika Egerer, Luis Manuel Navas-Gracia · Horticulturae · Spain

A study of twelve plots across four urban allotment gardens in Valladolid, Spain (Horticulturae, 2024) examined food production, cooling effects, and gardener perspectives. Crop selection matched broader Global North urban-gardening trends, adapted to limited plot space and varying by season. The gardens provided more stable and cooler temperatures than urban gray spaces, though the cooling effect was smaller than that of urban parks, and was most pronounced in summer. Greater crop cover at the plot level produced a stronger cooling effect, while crop abundance and diversity showed only a weak correlation with cooling benefits. Gardener surveys found awareness of climate change and its perceived direct threat to crops, health, and the city, along with concern about future water availability for crop growth and garden development.

Victor Crespo de Oliveira, Leonardo França da Silva, Érika Manuela Gonçalves Lopes, Ana Carolina Chaves Dourado, Matheus Mendes Reis, Bruna Nogueira Rezende, Letícia Duron Cury, Cássio Furtado Lima, Fabiane de Fátima Maciel, Silvana Ferreira Bicalho, Ariadna Faria Vieira · · Europe

Noting that global population growth is raising concerns about the sustainability of cities and soils, climate change, and food access and security, and that many urban areas face challenges related to their food supply infrastructure, this paper positions urban agriculture as a potential contributor to food security and income generation for impoverished households, while noting that conventional agriculture contributes to soil erosion and soil/groundwater pollution, and that climate change disrupts animal life cycles and drives species extinction, reducing food availability for humans and other organisms. Within this framing, the paper presents aquaponics as a method integrating urban agriculture for plant cultivation with safe fish production, and reports a project to develop and install an optimized aquaponics system at the School of Engineering, Polytechnic of Porto (ISEP). The soil-less vertical garden was built using two tanks holding approximately 2,000 liters of water, spanning three floors with three planter boxes and more than 120 positions for growing vegetables. Pedagogical activities were also carried out, involving students from Bioresources, Chemical Engineering, Biomedical Engineering, Electrical and Computer Engineering, Mechanical Engineering and Informatics Engineering.

Andreea Melinescu · Annals of the University of Craiova Series Biology Horticulture Food products processing technology Environmental engineering · Europe

This study focuses on designing a green space in the Old Town of Craiova, Romania. Using 3D landscaping software, a 270 m² area was designed with terraces covered in Wisteria sinensis, green walls, aromatic plants, and fruit trees, applying the Edible City Solutions concept, plus community-oriented elements such as a stage for events. The project is presented as a model for sustainable urban green spaces intended to enhance social interaction and environmental quality.

A. Fanny, António Ferreira, Paulo Conceição · Urban Geography · France

This paper analyzes social housing strategies grounded in "right-sizing"—including demolishing vacant housing, consolidating urban development, and converting vacant land into community gardens—in two shrinking French cities, Le Creusot and Montluçon. The analysis found that while both cities implement some quantitative adjustment of housing supply to demand, their actual strategies are considerably more complex, combining multiple synergistic lines of action, and the paper highlights that right-sizing as an analytical concept remains constrained by austerity principles.

Elżbieta Skorbiłowicz, Piotr Ofman, Mirosław Skorbiłowicz, Marcin Sidoruk, Urszula Tarasiuk · Water · Poland

This study assessed heavy metal contamination in 96 surface sediment samples collected from urban, agricultural, and forested areas of the Bug River catchment in Poland between July 2018 and 2020, measuring metals (Zn, Pb, Cr, Ni, Cu, Fe, Mn, Cd) by atomic absorption spectroscopy and applying the geoaccumulation index (Igeo), contamination factor (CF), and pollution load index (PLI). Urban sediments showed significantly higher heavy metal concentrations than agricultural or forested areas, with cadmium reaching up to 2.5 mg/kg; the average Igeo for cadmium was 0.24 in agricultural areas and 0.15 in urban areas, while the highest PLI values, reaching a maximum of 0.33, occurred in urban areas, and statistical analysis showed both urban emissions and agricultural activities significantly influenced heavy metal presence in the sediments.

Gemma Nohales, Mike Stinavage · Zero Waste Europe · Europe

The EU mandated separate collection of bio-waste across all Member States from 31 December 2023, but a LIFE BIOBEST survey of 14 Member States found economic, legal/administrative, organisational and technical barriers present in 86-100% of sampled countries. Only 7 of 27 Member States fully met the 2020 recycling targets, and only 9 are on track for the 2025 targets.

Claire Hamilton · BBC News · United Kingdom

In 2021 Liverpool City Council pledged to protect all 100 of the city's parks and green spaces — over 1,000 hectares of land — in partnership with charity Fields in Trust. By March 2024, only one, the park at Faulkner Square in the Georgian Quarter, had been formally placed in trust. The council said work was under way on 20 of the biggest and most strategically important sites, while local Friends groups expressed concern about the slow pace and development pressure.

UCL Institute of Education · UCL Institute of Education · United Kingdom

A UCL Institute of Education article on a partnership with the RHS training primary-education student teachers to use gardening as a teaching tool, describing an activity suitable for a class of 30 and featuring comments from participating staff.

Gabin Colombini, Fatima Senouci, Cornelia Rumpel, Sabine Houot, Philippe Biron, Axel Felbacq, Marie-France Dignac · Environmental Pollution · France

A 2024 analysis of archived soils from a long-term field experiment in France that received three urban composts — municipal solid waste compost, biowaste compost, and a sewage-sludge-plus-green-waste compost — over 21 years. Density fractionation followed by oxidation isolated 1,417 coarse microplastic (CMP) particles, identified by Py-GC/MS; different compost types produced different accumulation levels, and CMP content in soil rose over time. After 21 years the measured number of CMP particles matched estimates derived from compost inputs, but the measured mass did not for any of the three composts, which the authors attribute to biotic transport or to weathering and fragmentation making particles smaller. No difference in temporal pattern was found between films and fragments. The value of the study is long-term evidence that returning urban organic matter to soil also imports plastic; note that the site is farmland, not a city garden, so the figures cannot be transferred directly to citizen composting.

Daniel González, Raquel Barrena, Javier Moral-Vico, Ignacio Irigoyen, Antoni Sánchez · Waste Management · Spain

A 2024 study that measured methane and nitrous oxide (the main greenhouse gases), ammonia, volatile organic compounds (VOCs) and odour from several operating community composting sites in Spain treating kitchen waste, leftovers and household biowaste. Greenhouse-gas emission rates ranged from 5.3 to 815.2 mg CO₂eq per kg volatile solids per day and odour rates from 69.8 to 1,088.5 odour units on the same basis; both fell as temperature and biological activity declined with composting progress, and both were generally lower than rates reported for open-air full-scale composting plants. VOC families were most diverse in the early composting phases, while terpenes — limonene, α-pinene and β-pinene — were the most abundant throughout. The authors start from the observation that scientific data on gaseous emissions from community composting are scarce, which means that arguments about odour nuisance to neighbours have until now lacked measured reference values.

Stadtverband Leipzig der Kleingärtner e.V. · Stadtverband Leipzig der Kleingärtner e.V. · Germany

A page in which the Leipzig city federation of allotment gardeners collects national figures for the organised allotment system: 20 state federations, more than 13,310 clubs, 503 regional, district and area federations, and about 890,000 members. Counting family and friends, roughly five million people use a plot, and the nationwide average wait is three years. On costs it gives an average ground rent of 0.18 euro per square metre per year, working out at about 66.66 euro a year for an average 370-square-metre plot.

Alves, D., Villar, I., Mato, S. · Environmental Science and Pollution Research (Springer), 31(7):9873-9885 · Spain / Europe

A study comparing methodology, bulking agents, and compost quality across community composting centres (CCC) and community gardens used by local governments to treat biowaste. It shows how population density and the presence of green areas determine the siting of decentralized local composting infrastructure.

Wiśniewska-Paluszak J., Paluszak G., Fiore M., Coticchio A., Galati A., Lira J. · Land Use Policy 127:106562 · Poland, Italy

Uses the Business Model Canvas and Value Proposition Canvas to analyze urban farming strategies in Poland and Italy, identifying three business types (service-, product-, and land-use-oriented) and how each communicates value to market segments.

Szczurek A., Maciejewska M., Batog P. · Applied Sciences, 13(1):597 · Poland (Wrocław)

Develops and evaluates an automated monitoring system for urban beekeeping's educational, greening and awareness benefits. Sensors, cameras and scales were deployed on hives on the roof of a four-storey university building in Wrocław; three months of operation confirmed the system works and that rooftop placement is a viable urban apiary model.

Nicholls E., Griffiths-Lee J., Basu P., Chatterjee S., Goulson D. · Plants, People, Planet · United Kingdom

Study of crop-pollinator interactions in UK urban and peri-urban farms, quantifying ecosystem services provided by pollinators in city farming systems.

· Frontiers in Sustainable Food Systems · Germany

Analyzes Community-Supported Agriculture (Solidarische Landwirtschaft) in Germany as a form of food-democratic experimentalism, in which producers and consumers share the costs, risks and governance of production.

· Frontiers in Sustainable Cities · Germany (Freising)

Developed a holistic assessment of bee and flowering-plant diversity in the medium-sized city of Freising using citizen science, identifying 22 bee-diversity hotspots and evaluating planted flower patches as stepping stones for oligolectic bees.

Felderhoff J. · Ecological Applications · Germany (Berlin)

Documented 26 genera and 102 bee species across 18 Berlin community gardens, finding that higher plant species richness and greater deadwood amounts increased wild bee species number and functional diversity.

Herrmann J., Buchholz S., Theodorou P. · Scientific Reports · Germany

In German urban dry grasslands, examined effects of local habitat quality, urbanisation (impervious surfaces), and 3D connectivity on flower visitors; bee and butterfly species richness declined with increasing impervious surface.