Plants linked to lower levels of violence and self-harm in prisons

Green space has been shown to boost learning, improve recovery from hospital operations and lower the risk of mental disorders. Now the power of plants has been linked to lower levels of violence and self-harm in prisons.

Researchers mapped the percentage of green space – trees, lawns and shrubbery – within prisons in England and Wales and compared it with incidents of self-harm, prisoner assaults on staff and violence between prisoners.

Taking account of variables such as the age of prisons, their security level, population density, and whether they accommodated men, women or young offenders, the researchers from the University of Birmingham and Utrecht University found prisons with a higher presence of green space had lower levels of self-harm, and lower levels of assaults on staff and between prisoners.

The number of prisoners in England and Wales put on suicide or self-harm watch has risen by nearly 60% to 27,389 in a decade, with further rises during the coronavirus crisis.

There were more than 61,000 incidents of self-harm in English and Welsh prisons in the year to September 2019 alongside 33,000 incidents of violence between prisoners, and more than 10,000 assaults on staff.

The study, published in the Annals of the American Association of Geographers, suggests a modest 10% increase in green space inside a prison could reduce prisoner-on-prisoner assaults by 6.6%, with self-harm falling by 3.5% and assaults on staff by 3.2%.

“Our evidence shows clear and demonstrable benefits from the presence of green space for prisoners in all categories of prison,” said the lead researcher, Prof Dominique Moran of the University of Birmingham.

“It’s clear that inclusion of green space should be a key design element for new prisons, and existing prisons should convert existing outdoor areas to provide more green space wherever possible.”

The research has been shared with the Ministry of Justice, which is presiding over a crisis of rising levels of violence and disorder inside prisons after years of funding cuts.

The benefits of green space in urban settings have been widely demonstrated by three decades of scientific studies, alongside evidence of the specific benefits of trees and other green space around hospitals and schools.

Another study by Moran in one British prison found that outdoor green space and photographic images of the natural environment that took up a whole wall led prisoners to report restorative feelings of calm and the ability to reflect.

Previous research has revealed the benefits of gardening and vegetable-growing projects in prisons but some of those benefits are likely to only be experienced by participants who prosper because of teamwork or physical exertion.