Nationwide Research on the Rewilding of Kindergarten Yards (Vahvistu)

The prevalence of immune defence disorders such as allergies and autoimmune diseases has increased, while human contact with nature and the agricultural environment has decreased as society has become more urbanised. This is now thought to be due to the increased hygiene level associated with urban lifestyle and the reduction in microbial diversity in the habitat.

Previous studies have found a link between allergies and atopic dermatitis and exposure to natural microbes. This is thought to be due to the effect of microbial exposure on the development of a healthy immune system.

The Nationwide Research on the Rewilding of Kindergarten Yards (Vahvistu) is part of the Biodiversity Interventions for Wellbeing (BIWE) project, which is studying the effects of exposure of nature’s microbes on physical and mental health and wellbeing. The BIWE project aims to bring nature closer to people in the built environment where they spend their daily lives. Increasing the biodiversity of green spaces also supports human microbial diversity and thus immune function. Increasing the biodiversity therefore has a beneficial effect on the ecosystem, of which humans are a part.

A natural daycare or school yard promotes physical activity, immune balance, and creative play among children. Bringing biodiversity into the yard contributes to the wellbeing and positive mood of both the adults and the children.

What are we studying?

In this national research on the rewilding of daycare or school yards, we are studying how rewilding of yards contributes to children’s wellbeing and whether rewilding can prevent the development of immune defence disorders. The study is being carried out by the Natural Resources Institute Finland (Luke) and the Tampere University.

The regional administrative centres awarded 43 daycare centres or schools across Finland a total of around 1 million euros in state grants to improve the physical activity conditions and to rewilding the yards. The grants were awarded in 2023 as one-off projects, with construction starting in 2024 at the latest. We are carrying out the Vahvistu study in these daycares or schools.

We will include children from both the daycares or schools to be rewilded and control daycares or schools, where no green elements will be added to the yards. The content of the study is the same whether the child attends a rewilding or a control daycare or school. Children from the control daycares or schools will be sampled, take part in cognitive tests and answer questionnaires at the same time as children from the rewilding daycares or schools.

Branch 1: Sampling and survey

We research how increased microbial exposure from yard landscaping changes the microbial composition of children’s skin, saliva and faeces.

  • We research the function of the immune defence system from a blood sample.
  • We measure the level of the stress hormone cortisol in a small hair sample.
  • We use questionnaires to find out about the child’s health, well-being and lifestyle.
  • We ask parents about their smoking habits and medical history.
  • We test the child’s cognitive performance with a battery of psychological tests designed for this purpose.

Blood and hair samples are taken by the nurse and other samples are taken at home. Cognitive tests are carried out by a qualified person. Samples will be taken, questionnaires will be answered and cognitive tests will be carried out in the first year before and after the gardening, and then once a year for three years (2024-2027). At the same points in time, we will survey a wide range of health, well-being and lifestyle issues. In addition, a short questionnaire on infectious diseases will be answered every three months.

Files for families participating in the sampling:

Branch 2: Survey

Families may participate in a survey only. In this case, they will only receive surveys on health, outdoor activities and lifestyle, initially before and after the landscaping, and then once a year for three years (2024-2027). In addition, a short questionnaire on infectious diseases will be answered every three months.

The content of the questionnaires will be the same as for the sampled respondents. Questions will be about the child’s health, well-being and lifestyle. Parents are asked about their smoking habits and medical history.

We will send a link to the survey via the nursery’s mobile or internet app. The link can also be obtained by contacting us.

Files for families participating only in the surveys:

It is possible to participate in the research if your child is in the daycare or schools chosen for the research. Please contact us by email: Our researchers will be happy to tell you more!