Green gardens in the front reduce physiological and psychological stress

There is growing evidence that being in natural spaces – whether gardening or listening to birdsong – has a positive effect on mental health. Being in nature is also linked to improved cognitive function, greater relaxation, trauma management, and alleviation of some symptoms of Attention Deficit Disorder in children.

However, most of these studies have specifically examined the effect of public green spaces rather than private gardens. At a time when many people are at home due to COVID-19 restrictions, private gardens have been the most accessible green space for those who have them. But do these small 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 front (front yard) home gardens is associated with weaker signs of stress. As front gardens are increasingly paved by developers, we wanted to choose to look specifically at front gardens to understand their value and impact both mentally, socially and culturally. The front gardens are also a bridge between private and public life. Because they are visible to neighbors and passers-by, they can also contribute to the well-being of the community.

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

We added two planters with ornamental plants – including petunias, violas, rosemary, lavender, azaleas, clematis and a serviceberry tree (snowy mespilus) or dwarf juniper. 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 did all the plantings to make sure that all the gardens were similar. Participants were given advice on how to care for and water their plants and were allowed to add other plants or features. The new additions were as low maintenance as possible.

Less stress

Over a period of one year, we found that having plants in bare front gardens resulted in a 6% drop in the level of stress perceived by residents. 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 is equivalent to the long-term impact of eight weekly mindfulness sessions.

We also found statistically significant changes in the salivary cortisol profiles of the participants. 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 for good health, and levels usually peak upon waking and drop to their lowest level at night. The disturbances of this pattern indicate that our body is under stress. We found that 24% of residents had a healthy daily cortisol profile at the start of the study. This percentage rose to 53% three months after adding the herbs, 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 the gardens to have 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 in the face of stressful situations – and over time, have had an effect on their physiological response to stress, as measured by cortisol levels. A small addition of a few plants in the front garden has been a positive change in their home environment and on the street.

All of these green space wellness benefits 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 biophilia 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 directed attention. Spending time in natural environments requires less “brain power”, so to speak, because we don’t need to focus so much on specific stimuli or tasks, or suppressing distractions. Nature also offers us opportunities for reflection. Stress reduction theory proposes that natural environments cause instant emotional responses and fewer negative feelings than unnatural environments.

The results of our study show the importance of even small green spaces in reducing stress, and can be important considerations in local planning, urban development, and health and social care. An integrated reflection between the built environment, environment and health sectors is necessary.

The results of this project also support the social dossier in favor of a greater number of gardens and green spaces facing the street. For example, biophilic building standards, environmentally focused urban strategies, and pedestrian street initiatives could be important means of achieving this. It is important to note that for landscape architects and other professionals working with designed green spaces, there is considerable scope for impact on human perceptions, health and well-being.

For residents who have front yard space, planting designs can be low maintenance without taking up too much space. Container plantings can be the most attractive to tenants. But for those who don’t have access to an outdoor space, there’s some evidence that indoor houseplants offer mental health benefits as well.