The increasing complexity of urban regions and the lack of green areas in the neighborhoods have turned the cities less and less child-friendly. In order to locally face these situations, the project "Small steps of Agenda 21," which promoted a participatory planning experience for children focused on the green area of their school, was realized in the nursery school "J. Mirò" in Padua. During the project the children had the opportunity to be real protagonists of the improvement on the school garden while growing the awareness of the importance of discussion and participation in the local community. Results show that children improved their sense of inclusiveness and responsibility and prove that Agenda 21 processes are possible also in the nursery school.