This study examines an urban community gardening initiative with stated ambitions to contribute to both environmental and social sustainability in Stockholm, Sweden, through the lens of postapocalyptic environmentalism. Based on ethnographic fieldwork and qualitative interviews with gardeners as well as local officials, the analysis investigates the links between gardeners' postapocalyptic motivations, their practical work, and the wider institutional context. Rather than viewing postapocalyptic environmentalism as emerging outside of traditional institutions, the analysis reveals the initiative's entanglement and co-dependence on institutional structures and policies. The high level of institutionalization of urban community gardening locally requires the initiative to navigate the 'gray zone' between autonomy and co-optation and balancing between building 'small hope' through gardening work with actively confronting institutional challenges. Vague municipal guidelines, one-size-fits-all regulations and limited resources make urban community gardening in this setting vulnerable to participation fatigue as well as goal misalignment and co-optation.