Rooftop production of vegetables (#journal)

Rooftop production of leafy vegetables can be profitable and less contaminated than farm-grown vegetables

Urban agriculture may solve issues of feeding urban populations. It has been estimated that the total rooftop space in China is about 1 million hectares, some of which can be converted for rooftop farming. This article present here a feasibility study of hydroponically grown vegetables in a rooftop screen house in Guangzhou, China. None of the roof hydroponic vegetables exceeded the maximum residue limit for lead, arsenic, cadmium, chromium, mercury, or nitrate. In contrast, 5 of 98 market vegetables were contaminated by exceeding the maximum residue limit for lead. Similarly 3 were contaminated for arsenic, 23 for nitrate, and 2 for organophosphate or carbamate insecticide. Compared to high-end vegetables sold on the market, rooftop-grown vegetables were competitive in cost and quality. Given that many countries have limited arable land to feed a large population, the widespread adoption of rooftop hydroponics could help expand the total area available for food production.