Evidence of the benefits for STH

There is now a large and growing body of evidence from research relating to the benefits and efficacy of STH.

A recent review by Trellis on behalf of the emerging Association for STH (to support an application to the Professional Standards Authority for an accredited register of STH Practitioners) found over 130 relevant articles across 40+ journals.

In addition, there is a further body of research that looks at the positive effects of the processes that underpin STH, e.g. time in nature. The National Academy for Social Prescribing published an evidence summary for social prescribing and the natural environment, citing 75 research papers.

These studies include a small number of Randomised Control Trials and Meta-Analyses and many more small-scale evaluations. Some look at groups with specific health conditions or demographics, others are more general. We have selected the most compelling of the papers to support the information we present on the benefits of STH.

There are limitations to some of the existing research. The studies are often qualitative; the subject numbers in a study may be low; there may be no control group; RCTs are difficult in this context; measurement tools vary; the projects examined vary in type; and finally, there are more studies which look at nature-based activities, or at gardening generally than at green care interventions specifically or at STH projects. (Garside 2020, Wong 2022).

Note, many of these studies are not UK-based and use the term horticultural therapy (HT) to describe what we refer to as Social & Therapeutic Horticulture (STH).