The interest in urban farming is a phenomenon that occurs in both developing and industrialized countries. In the former mostly as a strategy to fight against marginalization and poverty, while in the later as both an alternative food network (AFN) and/or activity with aesthetic and environmental purposes. When dealing with productive agriculture, there is some conceptual confusion that often leads to failures in the calculation of environmental sustainability indicators based on density of green spaces in cities, by no considering as urban some agricultural activities clearly carried out within the urban ecosystem. After some conceptual considerations on urban agriculture, and some reflections on its strengths and its potential drawbacks, the case of the Urban Agglomeration of Granada has been analysed as an example of existence of intercalated farming area within the urban ecosystem, showing some inaccuracy in the use of conventional indicators of "greening" based on urban green density. Some conclusions have finally been drawn including the need to institutionalized a strong level of protection for these intercalated agrourban spaces.