Urban agriculture is sprouting throughout the world nowadays. New forms of urban agriculture are observed such as rooftop farming. In the case of low-tech rooftop farming projects, based on recycled urban waste, one of the key issues is the type of substrate used, as it determines the functions and ecosystem services delivered by the green roof. Using a five year experimental trial, we quantified the food production potential of Technosols created only with urban wastes (green waste compost, crushed wood, spent mushroom), as well as the soil fertility and the potential contamination of food products. Regarding food production, our cropping system showed promising results across the five years, in relation with the high fertility of the Technosols. This fertility was maintained, as well as the nutrients stocks after five cropping years. Most of the edible crops had trace metals contents below existing norms for toxic trace metals with nevertheless a concern regarding certain some trace metals such as Zn and Cu. There was no trace metal accumulation in the Technosols over time except for Zn. This study confirmed that constructing Technosols only from urban wastes is a suitable and efficient solution to design rooftops for edible production.

Since two decades, urban agriculture has been booming and a wide range of forms, from urban allotment gardens to rooftop farming under greenhouse, is developing. Various benefits are recognized for urban agriculture integration within the city and a specific consideration is dedicated to ecosystem services. In this article, we have focused on cultural ecosystem services provided by urban micro-farms. The state of the art reveals that urban agriculture delivers cultural ecosystem services that are well perceived and evaluated by users, but there are still few studies on this topic. Based on the analysis of specific literature on cultural ecosystems and micro-farms in parallel to a period of observation and documentary research of five urban micro-farms either on rooftop or at soil level, located in Paris and its surroundings, we proposed a specific methodology. This methodology aimed at quantitative and qualitative evaluation of the cultural ecosystem services provided by urban micro-farms and is based on a framework, which distinguishes exogenous and endogenous cultural ecosystem services.