During the past few decades, vertical farming has attracted a lot of interest as an alternative food production method. Vertical farms use engineered growth environments and hydroponic cultivation techniques for growing plants indoors. One of the important factors in vertical farming for the cultivation of different plants is the amount of nutrients, which can be measured as electrical conductivity (EC). Studying the optimal EC is important for avoiding nutrient loss and deficiency in vertical farms. In this study, we investigated the effect of five EC levels (2, 1.2, 0.9, 0.7, and 0.5 dS m⁻¹) of Hoagland nutrient solution on the growth and development of basil cultivar ‘Emily’ and lettuce cultivar ‘Batavia-Caipira’. During the study, the environmental parameters were kept fixed using an automatic dosing machine. The experiment was done in automatic vertical farms using the hydroponic ebb–flow cultivation technique with a temperature of 20 ± 1 °C, relative humidity of 50–60%, CO₂ concentration of 450 ppm, pH = 6, the PPFD (photosynthetic photon flux density) of 215 ± 5.5 μmol m⁻² s⁻¹, and the photoperiod of 16:8 h (day/night). Each treatment was replicated four times. We studied the effects on several growth parameters (including the dry and fresh weight of leaves and roots, number of leaves, and leaf area) as well as the chlorophyll and nitrogen concentration of the leaves. According to the results, the basil and lettuce growth parameters among the five treatments have been significantly higher in the treatment with EC of 1.2 and 0.9 dS m⁻¹. These EC values are lower than the recommended EC value given as the optimum in the previous studies. However, the concentration of chlorophyll and nitrogen show different trends and were higher in full strength of nutrient solution with EC = 2 dS m⁻¹.

Urban agriculture has a high potential to contribute to local circular economies, for instance by using nitrogen, phosphorus, and potassium in city organic waste streams as fertilizer inputs. However, inefficient use of waste-derived fertilizers could contribute to local water quality impairment related to nitrogen and phosphorus losses. Organic waste derived fertilizers are particularly challenging from a nutrient stoichiometry perspective, making over- and under-application of a particular nutrient likely. Where, and under what conditions, urban agriculture acts as a net positive for a circular nutrient economy vs. a nutrient water quality risk remains unclear. Here we review empirical peer-reviewed studies (2000–2021) on soil- and ground-based urban agriculture with a stated concern for nutrient losses to water. Of the 20 publications retained and reviewed (out of 241 screened), only seven measured losses to waters. There were four experimental studies, of which three measured nutrient leachate losses under different garden management practices. Of the 16 studies done in real-world conditions, only four quantified losses to water as leachate; average losses spanned 0.005 to 6.5 kg ha⁻¹ for phosphorus, and 0.05 to 140 kg ha⁻¹ for nitrogen. 13 of the 16 non-experimental studies provided data on nutrient inputs and harvested crop outputs, which could be used to calculate garden nutrient balances—an indicator of nutrient use efficiency. Although the value ranges were large, most studied gardens showed nutrient surpluses (inputs > crop harvest) for nitrogen and phosphorus (but not potassium); these surpluses were identified as a risk for losses to water. Contextual factors such as different access to fertilizers and knowledge, along with regulations and environmental factors can help explain the wide range of balance values and nutrient losses observed. Although a large surplus of inputs was often linked to increased leachate losses, it was not always the case in the limited number of studies we identified. Our review suggests that more field studies that measure losses to waters, and document contextual factors, are needed to determine how urban agriculture may contribute to a sustainable circular economy for all three nutrients without nutrient-related water quality impairment.

The agricultural sector in developing countries is one of the most vulnerable sectors to climate change and water scarcity. Iran is one Middle Eastern country facing a growing water crisis. Rafsanjan county, located in the province of Kerman, is losing its pistachio orchards to water shortages and climate change. The modernisation of irrigation methods and transfer of water from other regions have been the main strategies taken by the governmental authorities. The lack of success of these strategies has led to the emergence of more participatory approaches in the transformation of the agricultural sector and local urban planning in Rafsanjan. This study analyses the actor network of transformation in the agricultural sector and the rise of high-tech urban agriculture, and aims to understand the role of technologies in supporting citizen participation in local urban planning. The research draws on the concept of Technology-Driven Transitions (TDT). The interactions among social and materials entities and the impact of technological novelties on the re-configuration of their relationships in the transition process were studied. The research comprised an exploratory case study, and data were gathered through observations, document study and in-depth interviews with farmers, planners, researchers, and policy makers in Rafsanjan. The results of the study show that governmental planning organizations and their implementation bodies, such as the Agricultural Research, Education and Extension Organization (AREEO) and the 10-year plan for the development of greenhouses, were the most influential actants in the transition process. Their relationships with the other actants involved, such as the private sector, knowledge institutes and farmers, were re-configured by technological novelties. This re-configuration of relationships has led to strengthened participatory decision making in local urban planning in Rafsanjan.

Questions have arisen about the sustainability of the industrialised food system. Alternatives like urban agriculture have emerged to reduce the negative social, environmental and health impacts of industrial agriculture. Such new food supply chains can change the way that people acquire and process food. This study looks at high-tech indoor gardening practices in nursing homes for elderly people, studying four nursing homes in the Dutch city of Velp. We used both qualitative and quantitative approaches to collect data, using site visits, a survey amongst employees, and semi-structured interviewees with residents and decision makers. Inspired by social practice theory, we aimed to understand the transformation of existing practices, investigating how the gardens affect cooking and eating practices, and how their constitutive elements of meaning, material and competences enable these transformations. Our work shows that the indoor gardens resulted in an integration of gardening and the resulting harvest into cooking practices, which in turn transformed residents’ eating practices. Appreciation of the taste of fresh vegetables and appearance of the meal decorated by fresh vegetables, as well as observing the growth of plants and their use, holds value for the elderly residents. Employees welcome the possibility to serve healthier meals. The integration of indoor gardens in existing cooking practices is more successful when employees have gardening and/or cooking competences, when they enjoy cooking and when they do not already cook with fresh ingredients. The gardens are more easily integrated when they are easily accessible. The materiality of the gardens does not require fully equipped kitchens.