Front green gardens reduce physiological and psychological stress

It is becoming increasingly evident that being in natural spaces, whether while gardening or listening to birdsong, has a positive effect on mental health. Being in nature is also linked to better cognitive function, greater relaxation, coping with trauma, and relieving some symptoms of attention deficit disorder in children.

However, most of these studies specifically looked at the effect of public green spaces, rather than private gardens. During a time when many people are at home due to COVID-19 restrictions, private green spaces have been the most accessible green spaces for those who have them. But do these little green spaces have the same benefits for our mental health?

Although conducted before the current pandemic, my recently published study showed that having plants in home front gardens (front yards) is associated with lower signs of stress. As front gardens are increasingly paved by developers, we decided to look into front gardens specifically to understand what their value and impact was both mentally, socially and culturally. The front gardens are also a bridge between private and public life. Because they are visible to neighbors and passersby, they may also be able to contribute to the well-being of the community.

Our experiment evaluated physiological and psychological stress levels before and after adding plants to previously bare front gardens in Salford, Greater Manchester. We measured the participants’ cortisol concentrations (sometimes referred to as “the stress hormone”) in their saliva, as well as self-reported perceived stress. The participants were aged between 21 and 86, and 64% of them were women.

We added two planters with ornamental plants, including petunias, violets, rosemary, lavender, azaleas, clematis, and an amelanchier tree (mespilus nevoso) or a dwarf juniper tree. These were chosen for their ease of maintenance and familiarity with most people in the UK. We also provided the 42 residents with compost, self-watering containers, a watering can and a trellis. The research team performed all planting to ensure that all gardens were alike. Participants received advice on how to maintain and water their plants and were allowed to add additional plants or features. The new additions required as little maintenance as possible.

Less stress

Over a one-year period, we found that having plants in previously bare front gardens resulted in a 6% drop in residents’ perceived stress levels. This scale measures the degree to which life situations are considered stressful taking into account feelings of control and the ability to cope with stressors. The 6% decrease equates to the long-term impact of eight weekly awareness sessions.

We also found statistically significant changes in the participants’ salivary cortisol patterns. Cortisol is the body’s primary stress response hormone, which can activate our fight or flight response and can regulate sleep and energy levels. We need cortisol every day to be healthy, and concentrations typically peak when we wake up and gradually decrease to their lowest level at night. The disturbances in this pattern indicate that our bodies are under stress. We found that 24% of the residents had a healthy daily cortisol pattern at the start of the study. This increased to 53% three months after the plants were added, suggesting better mental health in these participants.

The reasons for these changes can be explained by what the participants told us during the interviews. Residents found that the gardens had a positive influence on their outlook on life, with strong themes developing around more positive attitudes in general, a sense of pride and a greater motivation to improve the local environment. The gardens were also popular as a place to relax.

These aspects are likely to contribute to people’s personal resilience to stressful situations and, over time, have had an effect on their physiological response to stress, as measured by cortisol concentrations. A small addition of a few plants in the front garden was a welcome change for the home environment and the street.

All these benefits for the well-being of green spaces are understood to be based on two theories of environmental psychology: attention restoration theory and stress reduction theory. Both psycho-evolutionary theories are based on Wilson’s biophilic hypothesis that humans have an innate affinity with the natural environment.

Attention restoration theory proposes that exposure to natural environments restores our ability to focus on tasks that require effort and direct attention. Spending time in natural environments requires less “brain power” so to speak, as we don’t need to focus as much on specific stimuli or tasks or suppressing distractions. Nature also offers us opportunities for reflection. The stress reduction theory proposes that natural environments cause instant emotional responses and fewer negative feelings than non-natural environments.

The results of our study show the importance of even small green spaces to reduce stress and can be important considerations in local planning, urban development and health and social care. Integrated thinking is needed between the built environment, environment and health sectors.

The results of this project also support the social case for more gardens and green spaces facing the street. For example, biophilic construction standards, environmentally focused urban strategies, and viable road initiatives could be significant ways to achieve this. Importantly, for landscape architects and other professionals working with designed green spaces, there is room for a considerable impact on human perception, health and well-being.

For residents who have front garden space, planting projects can require little maintenance without taking up too much space. Container plantations can be more enticing to renters. But for those who don’t have access to outdoor space, there is some evidence that indoor houseplants also provide mental health benefits.