Table 2.

Evidence summary: systematic reviews

Author, date and country	Aims	Type of gardens	Outcomes measured	Key findings	Authors’ conclusions
Cipriani et al, USA 32	To conduct a systematic review on the benefits of HT on persons with mental health conditions who are receiving services in either inpatient settings or outpatient community-based settings	HT**	Outcome measures reported in included studies: affect, agitation, behaviour/engagement, cognitive functioning, interpersonal relationship, physical well-being, psychiatric symptomatology, psychological/mental well-being, quality of life, self-esteem, sleep, social behaviour, stress and coping, volition, work behaviour. Tools reported in included studies: Affect Balance Scale, Test for Severe Impairment, Quality of Life Enjoyment and Satisfaction Questionnaire Short Form (Q-LES-Q-SF), Alcohol Craving Questionnaire, Post-traumatic Stress Disorder Checklist Civilian Version, Centre for Epidemiologic Studies Depression Scale (CES-D), cortisol levels, modified DCM (dementia care mapping) Scale, home-made assessment for behaviour and a modified DCM, interviews, The Bradford Well-Being Profile, Mini-Mental State Examination, Apparent Affect Rating Scale, Menorah Park Engagement Scale, Chinese version of Depression Anxiety Stress Scale 21, Work Behaviour Assessment, Chinese version of Personal Well-being Index, sleep diary, Modified Cohen-Mansfield Agitation Inventory, Revised Hasegawa Dementia Scale, Cohen-Mansfield Agitation Inventory, Physical and Mental Impairment Functional Evaluation, Multi-focus Assessment Scale for the Frail Elderly, Participation Index (Caplovitz) and Participation Index (Phillips), Volitional Questionnaire, Relationship Change Scale, Self-Esteem Scale, Social Behaviour Scale, Symptom Checklist 90 Revision, Evaluation of Horticultural Activity	14 studies were included in the review. Study designs include 5 randomised controlled trial, 6 cohort, 2 before and after, 1 cross-sectional. 11/14 studies found statistically significant findings in support of HT for at least one dependent variable. Studies were conducted in a variety of settings and mental health conditions. Limitations of the studies include, a lack of detail on the interventions in the included studies would limit reproducibility and a lack of information on the reliability and validity of outcome measures	Moderate evidence exists that horticultural therapy can improve client factors and performance skills
Genter et al, UK 44	To address the question, does allotment gardening contribute to health and well-being?	Allotment	Health, well-being. No other outcomes were included in the search strategy	10 studies were included published between 1999 and 2013, 7 qualitative studies, 3 quantitative studies. Overall, the review found that allotment gardening has a positive impact on health and well-being, provides a stress-relieving refuge and valued contact with nature, contributes to a healthier lifestyle, creates social opportunities and enables self-development. It was also found to reduce stress levels and increase positive mood. 3 qualitative papers found that allotment gardening is a suitable therapeutic group activity for people with mental health issues, while 4 papers recognised that individual and group allotment gardening supported healthy ageing	Allotment gardening has a positive impact on health and well-being. Allotment gardening can be recommended as a form of occupational therapy and can help promote health and well-being
Ohly et al, UK 86	To review whether school gardens benefited health and well-being of pupils and understand factors that enabled or challenged the success	School gardening	Studies were included if they reported quantitative or qualitative health and well-being outcomes. Outcomes reported include fruit and vegetable intake (structured dietary assessment method, Child and Diet Evaluation Tool (CADET), lunchtime observations, parent questionnaire, 24 hours recall workbooks, parent survey, Garden Vegetables Frequency Questionnaire, taste test); nutrients intake (CADET, 24-hour urine samples; flame photometry, Block Food Screener, Parent Questionnaire, 24-hour recall workbooks); physical (waist circumference, body mass index, and systolic and diastolic blood pressures, urinary sodium, total fat (%), GEMS Activity Questionnaire, Accelerometery, well-being (KIDSCREEN-10, Teacher Questionnaire, Quality of school life instrument, Youth Life Skills Inventory, Self-Report of Personality Scale for children and adolescents)	40 studies were included (quantitative n=24, qualitative n=16, mixed-methods n=3). Included studies were from the UK, Australia, Portugal and USA. Quantitative evidence was of poor quality often relying on self-report. Evidence for changes in fruit and vegetable intake was limited; 2 out of 13 non-randomised studies report a positive statistically significant impact of gardening on increasing intake of fruit and vegetables. 4 out of 6 studies found statistically significant changes in nutrient intake, one of which found a decrease in dietary fibre in the control group rather than an improvement in the intervention group. One non-randomised controlled study reported a positive statistically significant impact for diastolic blood pressure in favour of the intervention group, but reviewers note that all blood pressure readings were within normal range. One cluster-randomised controlled trial reported that children in the intervention group were ‘usually’ less sedentary and spent more time engaged in ‘moderate’ physical activity than control group, but when measured objectively, there was no increase in ‘light’ physical activity or decrease in sedentary behaviour. 2 out of 4 studies reported no difference in impact between a gardening intervention compared with a control group, data in the other 2 studies was found to be inadequate for assessment	There is limited quantitative evidence for the impacts of school gardens. Qualitative evidence suggests that participants of gardening programmes may experience or perceive a range of health/well-being outcomes. There are few studies that have used logic models to illustrate the impact of school gardens as complex interventions
Stern, Australia 94	To locate and synthesise best evidence about impact of physical activities on people with dementia	Gardening	The Diagnostic Statistical Manual of Mental Disorders was used to classify the absence or presence of dementia. Mental examination tools such as the Mini-Mental State Examination and activities of daily living	9/17 studies included in the systematic review looked at gardening as an intervention. Positive impacts of gardening were reported by one case-control study on a beneficial association with a reduction in the chance of developing Alzheimer’s disease. Two cohort studies found that gardening was significantly associated with a reduced risk of dementia (RR=0.53, 95% CI 0.28 to 0.99; HR, 0.64, 95% CI 0.50 to 0.83). Another cohort reported that exposure to gardening over at least 10 years may be associated with a reduced risk of developing Alzheimer’s disease	While the evidence is equivocal on whether participation in physical activities is protective against onset of dementia, gardening appears more beneficial than other types of activities. Data were extracted only for gardening
Wang et al, USA97	Systemic review evidence for beneficial effects of gardening on older adults	Gardening	Range of outcome measures, as authors sought to locate papers based on methodological approach rather than outcomes. Hence, outcomes were mixed and included Mini-Mental State Examination, Apparent Affect Rating Scales, nutrition Menorah Park Engagement Scale, Life Satisfaction Inventory, Stress tests, Perceived health and Well-Being Scales, self-reported pain, SF36, hand function, Self-Rated Health and Happiness Scale, Pearlins ad Schoolers Mastery Scale, sleep diaries, Modified Cohen-Mansfiled Agitation Inventory and Revised Hasegave Dementia Scale	22 articles were reviewed (adults). Through various research designs (quantitative and qualitative) and measurements used, the results reveal that gardening can be an activity that promotes overall health and quality of life, physical strength, fitness and flexibility, cognitive ability, and socialisation. The implementation of various aspects of gardening as health-promoting activities transcend contexts of practice and disciplines and can be used in urban and rural communities as both individual and group activities	The authors conclude that the literature reported variable findings, and while most of these were positive, the majority were at an exploratory stage. The evidence base provides an intriguing foundation for further research. Gardening has positive effects on older adults and help improve engagement and activity participation for people with dementia
Whear et al, UK 98	To examine the impact of gardens and outdoor spaces on the mental and physical well-being of people with dementia who are resident in care homes and understand the views of people with dementia, their carers, and care home staff on the value of gardens and outdoor spaces.	Garden visiting	Included studies had to report on agitation, number of falls, aggression, physical activity, cognitive functioning, or quality of life (quantitative) or report on the views of people with dementia who were resident in care homes, care home staff, carers, and families on the use of gardens and outdoor spaces (qualitative). (Tools reported in included studies—Agitation: Cohen-Mansfield Agitation Inventory (CMAI); Emotional outcomes: Affect Rating Scale)	A total of 17 studies were included (9 quantitative, 7 qualitative and 1 mixed-methods). Quantitative designs included 6 prepost studies, 2 randomised controlled trials, 1 prospective cohort, 1 cross-over trial. Quantitative designs were of poor quality but suggest a beneficial effect associated with garden use on reduced levels of agitation. There was insufficient evidence from quantitative studies generalising the findings on other aspects of physical and mental well-being. Evidence on the impact of HT was inconclusive	Garden use provides promising impacts on levels of agitation in care home residents with dementia who spend time in a garden. Future research should focus on using comparative outcome measures
Savoie-Roskos et al, USA 90	To identify the effectiveness of gardening interventions that have been implemented to increase fruit and vegetables consumption among children	Gardening	Fruit and vegetable consumption among children aged 2–15 years before and after implementation of a gardening intervention in a school, community or after-school setting	There were 14 papers located and included in the review. A total of 10 articles reported statistically significant increases in fruit or vegetable consumption for those who participated in the gardening intervention. The papers located varied in methodologies and many had small sample sizes and relied on the use of convenience samples, and self-reported measurements of F/V consumption. While the effects are small, the evidence reports a positive benefit on the consumption of F/V in the children who participated in gardening	The evidence suggests a modest but positive influence of gardens on F/V intake of children
Annerstedt et al, Sweden26	To systematically review the literature regarding effects of nature-assisted therapy (NAT), for patients with well-defined diseases, as a treatment option either alone, or together with other evidence-based treatment options	Gardens	Studies were included if they reported systematic review and meta-analyses of randomised controlled trials; randomised controlled trial's; non-randomised intervention studies, observational studies and qualitative studies. Nature-based, nature-assisted, gardening, horticulture, sociohorticulture, ecotherapy were included. A range of psychological, intellectual, social and physiological outcomes were included	38 papers (3 systematic reviews/meta-analysis, 6 randomised controlled trials, 12 non-randomised trials, 14 observational, 4 qualitative) published between May 1980 and 2009 were included. The authors report 13 significant improvements for psychological goals, 6 for social goals, 4 for physical goals and 2 for intellectual goals	The authors conclude that the evidence base reports a small, but reliable resource that highlights the benefits of NAT as an approach to promote health. Future studies should be adequately powered with clearly defined definitions
Kamioka et al, Japan60	To summarise evidence of randomised controlled trials on the effects of horticultural therapy	HT**	Inclusion criteria looked for all cure and rehabilitation effects in accordance with the International Classification of Diseases-10. Included studies reported on; Affect (the Apparent Affect Rating Scale) Engagement (Menorah Park Engagement Scale) Chinese version of Depression Anxiety Stress Scale 21 (DASS-21) Work Behaviour Assessment (WBA) Chinese version of the Personal Well-being Index (PWI-C) Life Satisfaction Index-A Form, Revised UCLA Loneliness Scale The Lubben Social Network Scale Self-esteem Scale, Powerlessness Beck Depression Inventory (BDI) Neurobehavioral Cognitive Status Examination (NCSE), motor-free visual perception test (MVPT) and functional independence measure (FIM)	4 studies met all inclusion criteria. All studies showed significant effectiveness in one or more outcomes for mental health and behaviour. No studies report cost-effectiveness. Methodological quality of the randomised controlled trials was low	People with mental and behavioural disorders such as dementia, schizophrenia, depression and terminal care for cancer, may benefit from HT, however the evidence supporting this is of low quality
Masset et al, UK75	To assess the effectiveness of agricultural interventions in improving the nutritional status of children in developing countries	Range for review including gardens	Dietary diversity, micronutrient intake, prevalence of undernutrition, participation and household income. Studies were included if they were cross-sectional and longitudinal project-control comparisons and randomised field trials and studies that compared participants and non-participants over a single cross-section	15 studies assessed the effectiveness of home gardens (1 randomised controlled trial, others longitudinal comparison and cross-sectional studies). A positive impact of home gardens was found on increased consumption of fruit and vegetables. No evidence of impact was found on iron intake in children. Some evidence of impact was found on improved intake of vitamin A among children <5 years (mean difference 2.4 µg/dL, 95% CI 1.67 to 3.16). Data for overall effects of garden interventions on children’s nutritional status not reported separately from other interventions. Methodological quality of included studies was poor	The review authors concluded that there was limited evidence of the impact of agricultural interventions on the nutritional status of children. The authors were unable to answer the systematic review question with any confidence due to the methodological weaknesses of the studies
Garcia et al, Brazil42	Systematic review to explore the impact of urban gardens on use of healthy food	Community gardening	Key nutrition-related outcomes; participation in urban gardens, food security, healthy food practices, increase in intake of fruit and vegetables, healthy diet and improved family nutrition. Impact on healthy food beliefs, healthy food access, reduction in food costs, greater interest in cooking and meal planning	24 studies were located. The studies were heterogeneous and included methodological flaws. People who participated in community gardens had improved healthy diet intake, shared food and valued healthy food. People who participate in gardens have an increased fruit and vegetable intake, improved access to health foods through harvest sharing and improved family diet	Community gardens can have a positive impact on food beliefs, knowledge and practices. Longer-term studies with more robust methodological frameworks are needed to verify the benefits of community gardens on nutrition and diet
Kunpeuk et al, Thailand64	Systematic review and meta analysis to explore association between community gardening, nutrition and physical health in adults	Community gardening	Diverse measurement units, but body mass index only was pooled to enable meta analysis	19 articles were included in the review. 14 cross-sectional, 1 case-control and four quasi-experimental. Results suggest a modest positive impact of gardens on body mass index reduction. A greater pooled effect size was reported for the subgroup analysis of the quasi-experimental and case-control studies	Gardens reduced body mass index and should be integrated into health policy
Nicholas et al, Singapore83	To assess whether HT was beneficial for older people	HT**	Psychosocial, QOL, SF36, Ryffs Scales of Psychological Wellbeing. Subjective Happiness scale, Personal Wellbeing Index, life satisfaction, dementia QOL	20 articles were included in the systematic review. 6 experimental studies of which 4 were randomised controlled trials. Other papers were quasi-experimental. Most studies reported significant effects of HT on a range of outcomes although there were mixed results on the effect of HT on function. Significant associations were reported on agitation, mood and engagement for people with dementia	The evidence for HT is promising, but more robust evidence is required to draw firm conclusions

F/V, fruit and vegetables; GEMS, Girls health Enrichment Multi-site Studies (GEMS) research team; HRQOL, Health Related Quality of Life; HT**, horticultural therapy; QOL, Quality of Life; SF36, Health Survey Questionnaire (SF-36); UCLA, Loneliness Scale.