Introducing Biomihiekka® microbial-sand that brings natural biodiversity and microbiota to urban playgrounds

Kekkilä launches the new Luontoleikki concept and Biomihiekka® microbial-sand, bringing natural biodiversity and microbiota to urban playgrounds. The new Finnish innovation, developed in collaboration with Uute Scientific, strengthens children’s immune systems.

Kekkilä Biomihiekka® is the world’s first microbial-sand designed to bring the diverse microbiota of nature safely into playground environments. The scientifically researched microbial extract supports the development of children’s immune systems and offers a new, public-health-relevant way to increase nature exposure in urban settings.

Nature-based playgrounds on the agenda of municipalities

Urban and municipal playgrounds are receiving new attention: discussions focus on how children’s everyday environments can support diverse play, a connection with nature and climate resilience – even when daily access to nearby forests is not possible. This is driven by growing understanding of the importance of natural materials and biodiverse yards in early childhood environments, as well as scientific evidence on the role of nature exposure and environmental microbiota in the development of immunity.

Programmes in Finland’s largest cities increasingly emphasise the addition of natural materials and multisensory environments. Playgrounds can also be used to address other urban development needs, such as stormwater management and improving the local microclimate. Nature-based, biodiverse yards are seen as essential for children’s wellbeing, climate adaptation and building a sustainable urban environment.

“We need to bring nature encounters to the places where children actually spend their time. That’s why nature exposure should be brought into everyday environments – it allows interaction with natural elements to take place effortlessly through play,” says researcher Olli Laitinen from Uute Scientific.

Hasselfors gardens Landscape
© Lena Larsson, 2025

Nature exposure delivered through playgrounds

For many children, early‑education yards are the most important outdoor environments of their daily lives, where they spend hundreds or even thousands of hours. The quality of these yards directly affects children’s opportunities for play, movement and nature experiences.

Playgrounds still often follow the same basic template, and truly diverse, multisensory play environments remain relatively rare.

Kekkilä’s Luontoleikki concept is designed to support children’s wellbeing, participation and equal access to nature. Based on Finnish research, the innovation brings forest microbiota into playgrounds.

The world’s first microbial-sand

Kekkilä Biomihiekka® combines play sand with a scientifically researched microbial extract that mimics the rich microbiological diversity of Finnish forest soil. It has been developed from the ADELE research project (Autoimmune Defense and Living Environment, Sinkkonen 2017, Puhakka 2019, Roslund 2022) in cooperation with Uute Scientific Oy.

Biomihiekka consists of screened play sand and the Reconnecting Nature™ microbial extract, which provides a scientifically proven positive microbial exposure as part of ordinary play. It can be used in sandboxes, large ground-level play surfaces and sensory areas.

Recent studies (ScienceAlert 2020, LettsSafari 2025) show that children playing in nature-enriched yards experience rapid and significant changes in immune function: increased T‑cell activity, more diverse skin and gut microbiota, and signs of reduced inflammatory tendency.

The microbiological quality of Biomihiekka has been verified in external laboratories, and the product functions in the same way as ordinary play sand.

More information:

Hannes Rummukainen
Senior Portfolio Manager, Landscaping & Recycling, Kekkilä-BVB

Olli Laitinen
Principal researcher, Uute Scientific