Background: There is increasing interest in the association between nature, health and wellbeing. Gardening is a popular way in which interaction with nature occurs and numerous gardening projects aim to facilitate wellbeing among participants. More research is needed to determine their effectiveness.
Aim: To systematically evaluate the effectiveness of group-based gardening interventions for increasing wellbeing and reducing symptoms of mental ill-health in adults.
Methods: A systematic review of Randomised Controlled Trials was conducted following the protocol submitted to PROSPERO (CRD42020162187). Studies reporting quantitative validated health and wellbeing outcomes of the community residing, adult populations (18+) were eligible for inclusion.
Results: 24 studies met inclusion criteria: 20 completed and four ongoing trials. Meta-analyses suggest these interventions may increase wellbeing and may reduce symptoms of depression, however, there was uncertainty in the pooled effects due to heterogeneity and unclear risk of bias for many studies. There were mixed results for other outcomes.
Research limitations/implications: Heterogeneity and small sample sizes limited the results. Poor reporting precluded meta-analysis for some studies. Initial findings for wellbeing and depression are promising and should be corroborated in further studies. The research area is active, and the results of the ongoing trials identified will add to the evidence base.
Keywords: Gardening intervention; green care; health promotion; horticultural therapy; mental health; social prescribing; wellbeing.