School greening interventions can support children’s emotional and social well-beingAs mental health difficulties are increasingly emerging in childhood, there is a growing need for strategies that support and protect children’s mental health throughout the primary school years. While exposure to nature is recognized as a promising approach for promoting children’s mental health, existing literature reviews have not specifically examined the potential mental health benefits of greening interventions in primary school settings. To address this gap, this systematic review used an evidence-mapping approach to synthesize the existing evidence on indoor and outdoor primary school greening interventions and their effects on children’s mental health and psychosocial well-being. The review also examined children’s preferences regarding the design of greening interventions, as well as the factors that may enable or hinder their implementation in primary school settings. Finally, the review identified key knowledge gaps and priorities for future research to inform the development of primary school greening interventions designed to support children’s mental health.
A systematic search was conducted to identify peer-reviewed journal articles examining the impacts of primary school greening on children’s mental health and psychosocial well-being. Greening was defined as an intervention to increase natural elements in the indoor or outdoor school environment. Studies were eligible for inclusion in the review if they involved primary school-aged children (age 4–13) and assessed outcomes such as stress, anxiety, depression, self-esteem, mood, emotional states, and social, psychological, and emotional well-being. Studies focused on green design and implementation enablers or barriers in school settings were also considered for inclusion. A range of study designs were eligible, including qualitative, quantitative, and mixed-methods studies that reported empirical primary data. Only studies published in English were included; however, no restrictions were placed on publication date. Twenty-two studies met these criteria and were included in the review and evidence map. The studies were conducted in 13 countries, primarily the US, the UK, the Netherlands, and Australia. One study was conducted in each of the following countries: Belgium, Canada, China, Germany, Indonesia, Malaysia, Spain, and Thailand. Sixteen studies investigated outdoor greening only, one investigated indoor greening only, and two examined both indoor and outdoor greening. Five studies utilized participatory approaches that explicitly involved children in the greening design and/or implementation. Most quantitative studies used quasi-experimental or other non-randomized designs; therefore, an appraisal of study quality ranked the strength of this evidence base as moderate. The qualitative studies were mainly rated as high quality. Analysis focused on synthesizing findings across studies to identify patterns and gaps in the literature.
A total of 13 studies examined the impacts of school greening on children’s mental health and psychosocial well-being. Among studies that assessed quantitative outcomes, four studies reported statistically significant positive findings on well-being measures after greening interventions and five studies reported non-significant findings. Positive findings included significantly reduced peer problems, decreased physical and verbal conflict, and improved social relationships one to two years after schoolyard greening. A study comparing lessons in a school garden with lessons in a traditional classroom reported that children had significantly higher levels of high-arousal positive emotions (happiness, pride, and wonder) and lower levels of fear and anxiety outdoors. Another study found that multiple measures of well-being significantly improved among male (but not female) students nine months post-greening. Among qualitative studies, six studies documented increases in high-arousal positive emotions, and five studies reported increased low-arousal positive emotions, such as peacefulness, calmness, and relaxation, after greening. Qualitative studies also reported reduced stress, improved social interactions and relationships, and an increased sense of confidence and belonging after greening.
Seven studies considered children’s design preferences for school greening. Findings here revealed six overarching themes: natural green elements, natural blue elements, structures, wildlife, indoor features, and the utility of green space. Most frequently, children wanted more plants incorporated into both the indoor and outdoor school environment. Blue elements, from small water features to larger ponds, were commonly requested. Children often supported combining natural elements with functional features, such as shaded areas and learning spaces. Children preferred natural elements that engaged their senses, including varied textures, scented plants, and sounds like running water or birds. They also valued the presence of wildlife. Children expected greening interventions to meet a range of needs, with areas for play, learning, and socializing, alongside quiet zones for relaxing in nature. Eight studies examined the factors that support or hinder the effective implementation of greening interventions. Factors enabling successful implementation and sustainability of school greening centered on school and community support, resources and materials, child participation in design and construction, curriculum integration, the roles of key personnel, and effective planning and preparation. Support from school leaders, staff, children, and parents was the most frequently reported enabler. Several barriers to school greening implementation were also identified. Challenges related to maintaining green spaces (e.g., mowing, weeding, watering) were reported most frequently. Other barriers included a lack of sustained support from the school community, safety concerns, and difficulty using green spaces for learning, particularly when staff lacked the knowledge or confidence to teach in nature.
Results indicate that increasing children’s exposure to nature in school through greening interventions may improve positive emotions and social functioning with peers in the schoolyard. The review also offers insight into children’s design preferences and the enablers and barriers to effective greening interventions. To maximize potential benefits, school greening initiatives should prioritize securing school and community support, engaging children in the co-design process, planning for maintenance needs, and identifying strategies to integrate greened areas into the curriculum. Research should continue to examine the mental health benefits of school greening. To strengthen the evidence base, the researchers recommend that future studies use experimental designs, validated mental health and well-being assessments, and longer follow-up periods to assess which benefits may emerge over time for children after school greening. Overall, the researchers conclude that “findings suggest that an expansion of greening interventions that take account of children’s preferences and engage school communities have the potential to transform the primary school environment with green spaces that may support positive mental health and well-being for children.”
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