Modern cities are largely sealed, climate controlled, and scrubbed-clean, and our homes have been isolated from nature’s microbial diversity. Scientists are increasingly concerned about the immune system’s deterioration due to this cleaner environment. It could increase the risks of allergies, asthma and inflammation.
The Finnish Institute for Health and Welfare and University of Eastern Finland researchers decided to test a radical but simple idea.
What if you brought forest microbes into your home?
The Finnish microbiome developed when forest soil was spread on the floors of their homes. It is more similar to outdoor microbes than human-associated ones.
According to the findings of the study, simple interventions, including accidental ones, could in future help improve home microbiomes, and rebalance them. It is particularly true for urban areas, where microbes in the natural environment are not as prevalent.
Martin Taubel, chief researcher and author of the article, said: The air was contaminated by bacteria associated with forest soil when forest soil is applied to a carpet. For the first two week after the application, the effect was more pronounced in the area where infants breathe. The signal could also be detected elsewhere around the house.
Microbes found in home environments are an important source of exposure for infants and children, who spend the majority of their day indoors. This can have a long-term impact on their health.
Lower exposure to microbes in the environment has been linked with asthma, allergies and inflammatory disease. In the search for better interactions, there is growing interest in improving indoor microbe exposure.
Researchers in this study investigated one of these tactics: placing forest soil on carpets at the front doors of Finnish houses to move environmental microbiota into the home. Six households in Finland took part in the 20-week research.
The researchers collected dust from the floors of homes, adult breathing zones and infant breathing zones.
The researchers tracked the bacterial and fungi communities using genetic techniques (amplisequencing & qPCR).
It was an easy intervention: Forest soil was repeatedly sewn onto the rugs at the entrance. The rugs were like “microbial gates” that circulated soil-associated bacteria inside.
After each seeding, the relative amount of soil bacteria found in dust increased. Within two weeks, the greatest effect was observed in airborne dirt in rug-soil areas and infants’ respiratory zones.
The diversity of bacteria increased, and the “asthma protective microbiota” index decreased. A home without pets, with little occupancy and mechanical ventilation would have the largest change in microbes.
University Researcher Pirkka Kirjavainen said, It was encouraging to learn that urban households could increase the microbial signatures linked with lower asthma risks with this simple and low-cost approach. Next, we will see if this intervention has the expected health benefits.
The study found that soil to rug intervention could alter the microbiome in homes.
Researchers are hoping that a flood of beneficial bacteria from the environment can be used to restore some immune-regulating exposures.
It is especially important to protect infants, as their immune system develops rapidly and they are susceptible to early microbial infections. Microbes that promote health could be targeted at infant breathing zones to prevent asthma and allergies.
Researchers cautioned that despite promising findings, further research is needed.
To ensure consistency in health, further research is needed to determine the appropriate “dose” and composition of microbe additions. The idea remains revolutionary. Instead of fighting the microbes that live in our home, we could learn how to grow them.
Journal Reference
- Taubel, M., Hill, M.S., Allard, S.
et al. A proof-of principle study on the transfer of environmental microbiota from forest soil to urban homes. Microbiome 14: 95 (2026).
DOI: 10.1186/s40168-026-02352-6
