A study in Finland has examined the impact of replacing artificial playground surfacing with natural materials, including soil, sand, moss, and forest floor elements, across multiple daycare centres. The project transformed conventional play areas dominated by rubber, gravel, and plastic into biodiverse environments designed to increase children’s exposure to environmental microbes.
The study involved approximately 75 children and compared those using “rewilded” playgrounds with those in standard urban play environments. Children were encouraged to engage directly with natural materials through digging, handling soil, and interacting with vegetation.
Findings showed measurable biological changes within weeks. Children exposed to biodiverse environments demonstrated reduced levels of harmful bacteria on their skin, changes in gut microbiota linked to lower inflammation, and increased levels of immune-regulating T cells. These results indicate improved immune system responses associated with regular interaction with natural surfaces.
