How Bringing Forests Into Preschools Boosts Children’s Health

Published: 29 October 2025. The English Chronicle Desk. The English Chronicle Online.

Aurora Nikula, five, enjoys a typical day at her nursery in Lahti, Finland, where she mixes sand, mud, and leaves to make imaginative “cakes.” For most kindergartens, this might raise hygiene concerns, but at Humpula daycare, children are encouraged to interact closely with the natural environment. Across Finland, 43 daycare centres have received a total of €1 million to “rewild” their outdoor spaces and expose children to diverse microbes found in soil, plants, and forests.

The initiative is part of an emerging body of research showing that human health is closely tied to the biodiversity of the environments we inhabit. Exposure to microbes from soil, plants, and forests can strengthen the body’s internal microbiome, particularly during the first 1,000 days of life when immunity and brain development are most critical.

At Humpula, the outdoor area resembles a miniature forest and allotment combined. Children forage, dig, and plant vegetables like carrots, beetroots, and courgettes in soil enriched with old leaves and forest matter. A 10-metre-square carpet of live forest floor, complete with moss and berries, has been imported to give children hands-on exposure to nature.

A two-year study including 75 children across 10 urban daycares compared “rewilded” centres with conventional asphalt and gravel yards. The results showed that children interacting with rich, biodiverse soil had fewer harmful bacteria on their skin, healthier gut microbiota, and stronger immune defenses. Within just 28 days, their T regulatory cells—which help protect against autoimmune diseases—showed measurable improvements.

Scientists emphasize that microbes in the environment transfer to humans through touch, ingestion, and even breathing. Soil, home to most of the world’s fungi, supports the microbiomes present in air, plants, and humans alike. Experts suggest that lack of early exposure to these natural microbes may contribute to allergies and autoimmune conditions.

The Finnish model is inspiring other countries. In Helsinki, a daycare is being redesigned with natural play areas, trees, rocks, and planters to replicate the benefits observed in Lahti. Research from the University of Sheffield further underscores the benefits of nature in education, showing that planting hedges around school playgrounds can significantly reduce pollution exposure and improve children’s health.

With biodiversity under threat globally, integrating natural spaces into preschools offers dual benefits: enhancing early childhood health while reconnecting children with the environment, providing a template that could shape healthier, greener futures worldwide.