Nature, Gardening, & Human Health

No description and no photograph can substitute for standing among real trees, surrounded by all the life that gathers around them in a true forest. Something about that experience reaches a person directly — a feeling no book or museum exhibit can recreate. A real forest also reveals something easy to miss from a distance: it is not only the trees that live there, but an entire web of interdependent life around them. 

— Maria Montessori, From Childhood to Adolescence

Nature Contact and Health

A growing body of research links direct contact with nature to a wide range of health benefits, both physical and psychological (Hartig et al., 2014; Keniger et al., 2013; Soga & Gaston, 2016). Urban green space in particular appears to play a meaningful role in public health (Groenewegen et al., 2006; Tzoulas et al., 2007). Richard Louv's well-known 2005 book argued that children's declining contact with the natural world contributes to a cluster of health and behavioral problems he termed "nature-deficit disorder" — a concept that more recent systematic reviews have lent some empirical support to, while noting that the evidence is still strongest for attention and emotional regulation rather than as a unified syndrome (e.g., Vanaken & Danckaerts, 2018, doi:10.3390/ijerph15122668; Zhang et al., 2020, doi:10.3390/ijerph17186640).

Earlier studies tied nature contact to outcomes including depression and anxiety (Beyer et al., 2014), birth weight (Dadvand et al., 2012), diabetes and obesity (Lachowycz & Jones, 2011), cardiovascular disease (Maas et al., 2009), and longevity (Takano et al., 2002). More recent umbrella reviews of the epidemiological literature (covering meta-analyses through 2024) continue to find that green space exposure is associated with lower all-cause mortality, lower cardiovascular and metabolic disease risk, healthier birth outcomes, and improved mental health — though the strength of evidence varies by outcome, and reviewers are increasingly careful to distinguish "convincing" associations from merely "suggestive" ones (Wang et al., 2025, doi:10.3389/fpubh.2025.1505292; Liu et al., 2023, doi:10.1016/j.envres.2023.116303). Reviews specific to children and adolescents similarly report consistent links between green space access and reduced emotional and behavioral difficulties, particularly inattention and hyperactivity, alongside more limited but still positive evidence for general mental well-being and depressive symptoms in teens (Vanaken & Danckaerts, 2018, doi:10.3390/ijerph15122668; Zhang et al., 2020, doi:10.3390/ijerph17186640).

Forest-specific research has expanded considerably in the last decade, much of it building on the Japanese practice of shinrin-yoku, or forest bathing. Multiple systematic reviews and meta-analyses published between 2019 and 2025 report measurable short-term reductions in cortisol and blood pressure, improvements in mood and anxiety, and some evidence for immune-related effects, plausibly linked to plant-derived volatile compounds (phytoncides) (Antonelli et al., 2019, doi:10.1007/s00484-019-01717-x; Qiu et al., 2022, doi:10.3390/ijerph20010458; Vermeesch et al., 2024, doi:10.1177/27536130241231258). At the same time, several of these reviews flag a real limitation worth stating plainly: many trials are small, short-term, and carry moderate-to-high risk of bias, so the size and durability of the effects are still being worked out even as the overall direction of the evidence holds up.

Taken together, this evidence base supports the idea that regular contact with nature functions as a form of preventive medicine, a view that has only gained traction since it was first proposed (Groenewegen et al., 2006).

Gardening as Everyday Nature Contact

Gardening is one of the most accessible and widely practiced ways people interact with nature. An estimated 117 million people in the United States — roughly one in three — garden (Statista, 2015); in Japan, around 32 million people, or one in four, garden daily as a hobby (Statistics Bureau of Japan, 2011); and in the UK, an estimated 27 million people, about 40% of the population, garden actively (Bisgrove & Hadley, 2002). Because gardening needs only a small plot of land, it scales easily into cities and towns, making it a practical way to counter what researchers call the "extinction of experience" — the gradual loss of everyday human contact with nature (Soga & Gaston, 2016; Soga et al., 2016).

Researchers and clinicians have paid increasing attention to gardening's health effects (Clatworthy et al., 2013; Genter et al., 2015; Wang & MacMillan, 2013). Studies associate gardening with gains in life satisfaction, vigor, psychological well-being, positive affect, sense of community, and cognitive function (Gigliotti & Jarrott, 2005; Gonzalez et al., 2010; van den Berg et al., 2010; Wakefield et al., 2007; Wichrowski et al., 2005; Wood et al., 2016), as well as reductions in stress, anger, fatigue, depression, and anxiety (Rodiek, 2002; Wichrowski et al., 2005; Wilson & Christensen, 2011; Wood et al., 2016).

Nutritional Benefits of Gardening

Beyond its psychological effects, gardening has a direct, mechanical link to nutrition: people who grow food tend to eat more of it. The strongest evidence for this comes from a small number of actual randomized controlled trials, supplemented by a larger body of observational research.

• The clearest causal evidence comes from the CAPS trial, a two-arm, observer-blind RCT in Denver and Aurora, Colorado, that randomly assigned adults either a community garden plot or a spot on a waiting list. Gardeners significantly increased their dietary fiber intake and physical activity, and also reported reduced stress and anxiety, relative to the control group (Litt et al., 2023, doi:10.1016/S2542-5196(22)00303-5). A companion analysis of the same trial found that gardening participants increased vegetable intake and seasonal eating specifically around harvest time (Alaimo et al., 2023, doi:10.1016/j.cdnut.2023.100077).

• In lower-resource settings, a cluster-randomized trial among women in rural Tanzania found that those who took up home gardening, with agricultural training and support, achieved meaningfully higher dietary diversity and a greater likelihood of consuming nutrient-rich food groups than women in the control villages (Blakstad et al., 2021, doi:10.1111/mcn.13096). A later cost-effectiveness follow-up on the same program is more cautious, noting that gains in dietary diversity didn't always persist once external program support ended — a useful reminder that gardening's nutritional benefits often depend on sustained support, not just initial access (Blakstad et al., 2022, doi:10.1016/j.foodpol.2022.102248).

• A 2022 review found consistent cross-sectional associations between community gardening and higher fruit and vegetable intake. (Hume et al., 2022, doi:10.1186/s12889-022-13591-1; see also Garcia et al., 2018, doi:10.1017/S1368980017002944). 

• In children, a systematic review of school garden-based programs across 12 countries found that shorter, smaller-scale programs without parental involvement tended to show the clearest gains in children's vegetable intake. (Chan et al., 2022, doi:10.1186/s12889-022-13587-x).

Horticultural Therapy: What the Newer Evidence Shows

Structured gardening-based treatment — horticultural therapy — has moved from a promising idea to a more rigorously tested intervention over the past decade. Two earlier systematic reviews (Genter et al., 2015; Wang & MacMillan, 2013) first mapped out the field, but the evidence base has since deepened considerably:

• Depression: A 2022 systematic review and meta-analysis found horticultural therapy meaningfully reduced depressive symptoms in older adults (Zhang et al., 2022, doi:10.3389/fpubh.2022.953363), and a 2025 analysis examining program duration and frequency found that shorter, more intensive programs (roughly 5–8 weeks, sessions over 60 minutes, fewer than 3 times weekly) tended to outperform longer, more diffuse ones for this outcome (Chen et al., 2025, doi:10.3389/fpsyg.2025.1575441).

• Dementia and cognitive function: Meta-analyses through 2024 report improvements in cognitive function scores, depressive symptoms, daily functioning, and quality of life among older adults with dementia (Tu & Chiu, 2020, doi:10.1038/s41598-020-71621-7; Wang et al., 2024, doi:10.1111/jocn.17444).

• Anxiety: A 2025 Systematic review and meta-analysis found a large, statistically significant effect on depression, and a moderate but still significant effect on anxiety (Wood, Barton & Wicks "Effectiveness of Social and Therapeutic Horticulture for Reducing Symptoms of Depression and Anxiety: A Systematic Review and Meta-Analysis," Frontiers in Psychiatry, doi:10.3389/fpsyt.2024.1507354.)

• Schizophrenia: A 2024 meta-analysis of 35 randomized controlled trials (almost 2,900 participants) found horticultural therapy produced meaningful reductions in total symptoms, with the clearest effects on depression and anxiety, though the authors note most trials were conducted in Asia and few were formally registered (Lee et al., 2024, doi:10.3390/healthcare12212104).

The overall picture from this more recent literature is that horticultural therapy has reasonably strong support as a low-cost, low-risk adjunct treatment for several populations.