Could rooftop gardens be the key to urban self-sufficiency?
Rooftop gardens have the potential to produce significant levels of fresh fruit and vegetables, giving urban populations access to fresh, healthy and affordable food. As well as providing fresh food, such gardens also help to increase biodiversity, filter polluted air, absorb excess carbon dioxide and decrease inner city temperatures.
These claims come from a recent study into rooftop agriculture, which has been taking place in Bologna (Italy) since 2010. Three different growing systems were trialled by participants: plastic pipes, recycled pallets filled with compost, and polystyrene panels floating in tanks (also made from recycled pallets). A variety of produce was grown, including lettuce, black cabbage, chicory, tomato, aubergine and melons.
Using results from the initial trials, gardeners designed a growing system incorporating the best results from each of the different technologies. The system was designed for a 2016m² rooftop garden and is calculated to be able to produce three tones of vegetables per year. Digital maps and computer-aided design software helped researchers identify 0.82km² of unused flat spaces on Bologna’s roofs and terraces. If all this space was used for gardening, Bologna could produce around 12,500 tonnes of vegetables on its rooftops alone.