Psychological restoration in urban gardens related to garden type, biodiversity and garden-related stress

In the context of increasing urbanization, gardens as a form of urban greenspace are an important resource for the psychological restoration of urban dwellers, while underpinning urban biodiversity and delivering ecosystem services. However, the links between restoration, garden type and biodiversity are not fully understood. In this interdisciplinary study we aimed to identify how the self-reported restoration of gardeners was related to three factors: garden type (domestic vs. allotment gardens), number of plant species in the garden (a dimension of biodiversity) and garden-related stress for gardeners. We analyzed cross-sectional data of approx. 300 leisure gardeners in the city of Zurich, Switzerland, using an analysis of spatial autocorrelation, t-tests of differences of means between garden types and a structural equation model (SEM). The results indicated that being an allotment gardener was associated with higher levels of restoration compared to domestic gardeners. The SEM suggested that restoration was positively related to the number of plant species by way of the perceived restorativeness of the garden. Garden-related stress or negative affect occurred among a number of gardeners and was negatively related to the restoration outcome. This suggests that the negative effects of gardening should be considered in future studies on greenspace and restoration. In the face of shrinking urban greenspace, our study suggests that urban planners could better utilize the benefits of urban gardens, e.g. to reduce income-related health inequalities by providing gardens to residents with lower socio-economic status or to address public health and ecological issues by promoting plant-species rich gardens.