Human Health & Plants Research: Study of the Benefits of Horticulture for People with Mental Illness

Dr. Charles Guy

The idea of digging in a garden and engaging in agriculture as being beneficial for mental illnesses dates to the writings of Dr. Benjamin Rush in the early 1800s. Recently Siu and colleagues1 conducted a study of the outcomes of a horticultural therapy program on people with long-term mental illnesses using a mixed-methods approach of quantitative and qualitative measures. The study recruited 82 adults interested in horticulture and plants who were enrolled in daytime vocational programs. Participants were randomly assigned to continue in their vocational programs as a control (41) to those assigned to a horticultural therapy (HT) program as the treatment (41). The experimental design involved a pretreatment baseline assessment, immediate posttreatment assessment and a follow-up.

The average age of participants was 50.3 years, and 55 percent were women. The average onset of illness was 25 years previous to the study. Participants in the HT group received eight 75-minute sessions of horticultural activities that included transplanting, vegetative propagation using cuttings and division, mindful eating of fruits, introduction to aromatic herbs, vegetable harvesting, and making small container plant arrangements, leaf rubbings and pressed flower cards. The HT treatment was administered to small groups of 8-10 participants.

Mental health was evaluated for indications of depression, anxiety and stress using the DASS21 self-report questionnaire. The Mental Well-Being Scale was used to assess overall psychological well-being. The EMAS questionnaire evaluated participants’ sense of engagement, accomplishment and meaningfulness. Additionally, engagement and affect during the HT sessions and social exchange and support were examined.

The study results suggest that the HT program treatment group showed statistically significant improvements for engagement and mental well-being and a positive sense of meaningfulness and accomplishment relative to the comparison group. However, contrary to many previous studies, the HT treatment did not improve indications of depression, anxiety and stress in the present study. It remains unknown why there appeared to be no treatment effects for depression, anxiety and stress in this study.

The present study provides additional evidence that aligns with the writings of Benjamin Rust that gardening and agriculture can be beneficial for people suffering from mental illnesses.

1Siu, A., Kam, M., Mok, I. (2020). Horticultural Therapy Program for People with Mental Illness: A Mixed-Method Evaluation. International Journal of Environmental Research and Public Health, 17(3), 711.

Charles Guy, Emeritus and Courtesy Professor
Department of Environmental Horticulture, University of Florida