Numerous barren land areas are found within administrative boundaries of cities. They include both former farmland located at the outskirts of cities, as well as vacant plots, postindustrial plots or former railway infrastructure plots. Barren plots are integral elements of the urban landscape and contemporary scientific concepts indicate their important role in the functioning of urban ecosystems. Abandoned land provides a potential for the development of green infrastructure and further development of recreation areas. At the same time some abandoned plots are informally adapted by local residents to suit their needs, transforming them into community gardens and recreation areas. This paper presents results of studies conducted by the authors in selected derelict areas in the city of Poznań. Analyses were conducted on their type, origin, size and location within the city. Observations were also recorded on the methods to adapt abandoned land by local communities.