Author(s)

YI-HSUAN HSIEH, JUNG-TE HSU & TING-I LEE

Abstract

More than half of the global population has chosen to live in urban areas than in rural areas. This results in issues on sustainable food provision in urban areas. Transporting vegetables and fruits from the countryside to the city while keeping them fresh consumes energy and causes loss. Given the cost, growing food in and around cities has never been a new thing. However, only recently, growing food on rooftops on a business scale to achieve self-reliance has increasingly gained attention. With current technological advances in horticulture and agriculture, it has become more likely to secure food provision by cultivating on urban rooftops. Only a few business scale cases reported in high-income societies with a high-density population or experiencing snowing winter can afford and justify the choice of such a high input as well as a high-yield cultivating system. In Taiwan, with a warm winter, it may be more feasible to apply this system because less energy input is required to achieve the same yield as compared to that required in places  in temperate climates. By estimating the potential of a high-density city to achieve self-reliance through rooftop growing systems, decision-makers can have more insight into how the idea can be promoted. As of end 2016, Chiayi city has the second largest population density after the capital city. Thus, this research aims at assessing the potential to achieve self-reliance by growing food on rooftops in Chiayi. It analyzes the yields of four types of rooftop cultivating systems and estimates the production and consumption by using these systems on three types of rooftops in different land uses, namely commercial, educational and residential. The result shows that the best scenario for achieving self-reliance is the rooftop hydroponic greenhouse model operating at the commercial scale although this is not sustainable or practical for general households in Chiayi City.

Keywords

Food security, roof garden, rooftop farms, scenario analysis, self-reliance, urban agriculture, urban farming, urban food system