GardenUp: A citizen science tool to assess ecological, social, and economic sustainability in private gardens

Private gardens are increasingly recognized as important components of (urban) green infrastructure, contributing to biodiversity and human well-being. However, they remain understudied due to limited access and the absence of systematic tools for evaluating sustainability in these semi-private spaces. This paper presents the development and application of a citizen science-based digital tool ( GardenUp ) designed to assess gardening practices across ecological, social, and economic dimensions. Using self-reported data from 434 German garden owners, we describe the current state of sustainable behaviors in private gardens and identify three gardener profiles—most sustainable, moderately sustainable, and least sustainable—who differ in both practices and socio-demographic characteristics such as garden size and owner age. Overall, our findings reveal fragmented patterns of sustainability and highlight behavioral gaps, offering concrete entry points for urban outreach and greening programs. The underlying framework is transferable and may support both research and planning efforts seeking to better integrate private green spaces into broader sustainability strategies.