Effect of gardens & gardening on human health

This page is an archive of older news stories from around the world. You might find these references useful if you're researching the benefits of gardening or exposure to nature on human mental or physical health and wellbeing. If links to media releases no longer work, you might still be able to use the information to locate the original research papers.

Check the Queensland Gardening Pages front page for more recent news items, or if you're interested in plants or horticulture in Queensland.

Courting Coolness

A study conducted in Potsdam, Germany, compared four comparable urban spaces surrounded by five-story apartments. They found that even small differences in the amount of greenery produced benefits for residents, particularly summer cooling. The presence of trees and shrubs reduced temperatures up to 11°C in these courtyards. The maximum value recorded in the least-vegetated courtyard during the study was 45°C, demonstrating that even in northern Europe, humans can be at risk of heat stress. If such events become more frequent, the need for sustainable mitigation measures becomes even more important. Sources: Green backyards help increase urban climate resilience: Here is how, Ecosystem-based adaptation to climate change through residential urban green structures: co-benefits to thermal comfort, biodiversity, carbon storage and social interaction, One Ecosystem (January 2022)

Wonderful Woodlands

Among the studies revealing the positive effects that a vegetated environment has on mental health is a new one involving adolescents in London. It focussed on the 9-15 age range, which is thought to be a key period for development of reasoning and understanding. The researchers found exposure to woodland (not grassland) was associated with higher cognitive development scores and a lower risk of behavioural and emotional problems. Other green space has a smaller benefit but no effect was observed from proximity to blue space (rivers, lakes, sea). Sources: Living near woodlands is good for children and young people's mental health (July 2021)

Get Your Daily Dose

It's well established that gardening is associated with mental health. A study out of the UK has looked at the "dose" you might need. The researchers found gardening 2-3 times per week was effective, but daily was even better at lowering stress and improving wellbeing. Source: Daily gardening is as good for mental wellbeing as regular vigorous exercise (April 2021)

Does Darkness Cause the Green Space Effect?

A lot of research has shown that green space in urban environments improves human health in various ways. The authors suggest that this be addressed in future research, to determine whether the best outcomes can be obtained from more green space, less light exposure at night, or both. Source: Green space or light at night - how do we improve health? (March 2021)

A Prescription for Street Trees

Consistent with growing evidence of the therapeutic effects of a vegetated urban environment, analysis of the population in Leipzig, Germany has shown that streets trees can improve mental health. Researchers used the number of prescriptions for antidepressant medication in different parts of the city as the gauge. They found that a high number trees within 100 metres of the home made a difference, particularly among socio-economically disadvantaged groups. These are also the ones most at risk, so planting of more street trees could help address inequalities in this aspect of health. The species or diversity of the trees did not make a difference in this study, nor did the number of trees more than 100 metres away from home. Source: Street trees close to the home may reduce the risk of depression (January 2021)

Reducing Brain Strain

In research (https://doi.org/10.1098/rsos.201100) that will be of particular interest to work-from-homers, the gait of people walking towards a projected image was analysed. Speed and step length suffered more when urban scenes were viewed compared to natural ones. In a second experiment, the researchers gave participants a simple shape discrimination challenge while being distracted by the same scenes. Reaction times were slowed by presentation with the urban imagery compared to the nature scenes. These results indicate that even dealing with the visual aspects of a city can have a negative effect on the brain's ability to perform other tasks. (January 2021)

Tree Benefits Add Up

Analysis of hundreds of public schools in Washington State, USA has shown that green cover - specifically tree cover - within 250m of the school enhanced performance in reading and maths in sixth grade children. Other research examining the positive relationship between nature and learning have concentrated on younger or older students. Source: Trees set sixth-graders up for success (November, 2020)

Greening Daycare Delivers Health Boost

Finnish researchers took the barren playgrounds of urban daycare centres and made them more like a forest floor by the transplantation of assorted shrubs, grasses and mosses plus soil. Planter boxes for planting with annuals and peat blocks for climbing and digging were also added. Measured improvements in skin and gut microbiota and immune systems indicated that child health can be boosted by playing in and with a more diverse and natural environment and this can be achieved by renovating existing playgrounds. Changes were seen in just one month. Source: City Day Care Yards with Forest Floor Boosted Children’s Immune Systems (October 2020)

Little Gardens Can Be Uplifting

A number of small, bare front gardens in an economically deprived region in the north of England were the basis of a study. Some received an allocation of ornamental (not edible) plants of various sizes, installed in self-watering containers that were maintained by the researchers. In the months that followed, residents of those homes showed improvements in diurnal cortisol patterns and self-reported emotional responses. Although access to public green spaces and communal gardens may have their own benefits, this study indicates that urban planners should not overlook the contribution that private gardens can make to the health and well-being of a population. The intervention motivated some of the participants to improve the gardens further or start working on their back yards or house. It even inspired some of the neighbours. Full report published in Landscape and Urban Planning: “It made me feel brighter in myself”- The health and well-being impacts of a residential front garden horticultural intervention (October 2020)

A Green Gaze Reduces Stress

A study conducted in a real-world office in Japan asked participants to keep a small plant on their desk. They were also required to gaze at the plant for 3 minutes when feeling fatigue. These little "nature breaks" were beneficial to the workers. The researchers suggest that choosing and caring for the plant may have enhanced the positive results observed. The type of plant chosen was not important and they were not large. They included small succulents, bonsai, kokedama and tiny air plants. Sources: Plants can improve your work life, Potential of a Small Indoor Plant on the Desk for Reducing Office Workers' Stress. (January 2020)

National Parks' Hidden Productivity

An interdisciplinary team of Griffith University researchers have estimated that the improved mental health of visitors to national parks is worth about $8.7 trillion ($US6 trillion) per year worldwide. The value of Australia’s national parks to the nation is estimated at around $145 billion a year, meaning the cost of poor mental health to Australia could be 7.5% higher without national parks and other protected areas. Source: Research estimates value of impact national parks have on mental health. Full report: Economic value of protected areas via visitor mental health, Nature Communications. (November, 2019)

Horticultural Rehabilitation

A 5-year study tracked released prisoners to see if horticultural community service, done as part of probation or parole requirements, could reduce the likelihood of individuals re-offending. Indeed, those involved in some form of horticultural work were less likely to recidivate than those doing non-horticultural tasks. Of the non-horticultural group, those working outdoors fared better than those indoors. Any form of community service was, on average, much better than none at all at helping former prisoners find a new place in society but exposure to nature seems to have additional positive influence. Source: Combating Prison Recidivism with Plants. Full report: The Effect of Horticultural Community Service Programs on Recidivism (September, 2019)

Look to the Trees

A study conducted in Australia is in line with international research that a vegetated landscape is good for us. What's more, it indicates that the presence of trees is crucial. Data was collected from residents of Sydney, Wollongong and Newcastle aged over 45. It was found that 30% or more tree canopy cover in the district was associated with lower odds of psychological distress while but that an equivalent area of just grass actually increased them. Similar results were found with respect to self-reported feelings of general health. Low-lying vegetation did not seem to have much effect one way or another. Sources: Urban trees found to improve mental and general health, Association of Urban Green Space With Mental Health and General Health Among Adults in Australia. (July 2019)

Cultivate health

A new analysis of US data has shown that even quite short periods of moderate physical activity - which includes gardening - could improve health. Just 10-59 minutes per week was associated with a 18% lower risk of death from any cause, compared to people who were inactive. More time or more vigorous activity had even better effects. Source: Even low levels of leisure time physical activity lowers risk of death In another study published in the same month, a 14% reduction in risk of death was observed among low-activity participants who replaced 30 minutes of sitting time per day with light physical activity.Source: Replacing Sitting Time with Physical Activity Associated with Lower Risk of Death (March 2019)

Growing brains

Recently released results of a psychological study suggest greener neighborhoods may improve children's brains. 11-year-olds living in urban areas of England were assessed. Even after allowing for socio-economic factors associated with neighbourhoods, more greenspace was correlated with better spatial working memory. This cognitive function records and processes information about an individual's surroundings and is related to attention control. It's also correlated with academic achievement. While this study couldn't prove that the environment directly caused the better memory performance, it points the way to further research and another possible benefit of more parks and gardens in cities. Source: Greener neighborhoods may be good for children's brains. Full report: The role of neighbourhood greenspace in children's spatial working memory (September, 2018)

Mindscaping

Status of a study's participants living near vacant lots in Philadelphia, USA were recorded before and after the lots received different levels of rehabilitation. Those within a quarter-mile radius of greened spaces averaged a 41.5% reduction in feelings of depression compared to those near lots that remained abandoned. A basic clean-up of trash without addition of grass and trees had no effect. Full report: Effect of Greening Vacant Land on Mental Health of Community-Dwelling Adults JAMA Network Open (July, 2018)

Horticultural therapy promising for the aged

Elderly women who took part in a 15-week gardening program showed improvement in physical health and mental function while nonparticipants declined, a South Korean study shows. Satisfaction with the program as a physical activity was very also very high. Source: The many health benefits of gardening for elderly women (October, 2016)

Gardens make you feel better than balconies

In Austria, 811 people across a wide age range were questioned about their restorative value of their private lounges, terraces, balconies and gardens. Gardens were rated significantly better than balconies or terraces, with the restorative value increasing with the number of "natural elements" present in the garden. Age or gender made no difference, but the reported effectiveness of gardens did depend on the individual's ability to switch off from their worries and having a positive relationship with their gardens. "The message is that you should design your garden to be as close to nature as possible but, above all, you should enjoy it." A second study is further investigating the health-promoting effects of private gardens as well as more communal gardens. Source: Public Health Study: private gardens are more restorative than lounges (April, 2016)

UQ investigates office greenery

A collaboration between the University of Queensland and several international universities has studied the effects of plants in offices. The results suggest that increases in worker happiness and productivity will make the investment in office greenery worthwhile. Source: Leafy-green better than lean (September, 2014)

Childhood obesity intervention with gardens

A study of English children has shown that those in lower educated households, or those in higher educated households located in disadvantaged neighborhoods, that have no access to a garden between the ages of 3-5 years have an increased risk of obesity by age 7. Source: Study from England shows no garden access for young children linked to childhood obesity later in childhood (September, 2015)