Productivity of a building-integrated roof top greenhouse in a Mediterranean climate

Urban Agriculture (UA) is an emerging field of agricultural production aimed to improve food security and the resilience of cities and to improve the environmental, social, and economic sustainability of urban areas. One of the options of UA are roof top greenhouses (RTGs), which are greenhouses built on the roof of a building, typically fitted with soilless culture systems. Further benefits can be achieved if the greenhouse and building are integrated, so that they exchange and optimise energy, water and CO2 flows. Integration is possible if the RTG and the building can exchange air and can collect rain water or use properly treated grey water for irrigation. Such type of integrated RTG is referred to as i-RTG. Both the environmental profile and the social value of i-RTGs have been studied, but information on their productivity is rather scarce. As the economic viability of i-RTGs is given by the value of all services provided, including the yield, the productivity of such systems needs to be maximised. This study attempts this, through the analysis (and discussion) of an i-RTG built in a Mediterranean climate (Barcelona area, Spain), producing beef type tomatoes (“Coeur de boeuf” cultivar).