Currently, urban areas are becoming more susceptible to climate-related risks such as urban heat island effects, biodiversity loss, food insecurity, and increased social fragmentation. Although Nature-Based Solutions (NbSs) have been recognized as a key approach to addressing these issues, their socio-ecological characteristics have been less explored. This paper seeks to re-conceptualize communal gardens as socio-ecological infrastructure that encompasses collective governance as well as environmental adaptation in European capital cities. To carry out this study, a multi-scalar approach is utilized. First, this paper examines climate action plans of selected European capital cities to determine how communal gardens feature in urban adaptation strategies. Second, spatial analysis of communal gardens is carried out to assess their role in regulating urban microclimates and promoting biodiversity ecological connectivity. In addition, governance systems, participation mechanisms, and collective management of communal gardens are also evaluated to determine their role in collective governance. The study reveals that communal gardens are hybrid infrastructures that reduce microclimate effects, increase biodiversity, and improve soil permeability, as well as fostering social cohesion, food security, and participatory governance. Their adaptability is seen not only in their ecological performance but also in their capacity to integrate ecological functions with social cohesion and place-based identity. By considering communal gardens as socio-ecological systems, they contribute to developing a framework for integrating community-oriented, nature-based solutions into urban climate policy. They also provide transferable knowledge for other cities aiming to harmonize climate adaptation, social equity, urban common spaces, and resilience.