A team of researchers from Stanford University has come to an unexpected conclusion: an excess of plants in the workplace doesn’t reduce stress — it actually increases it among office workers. The finding challenges the widely held belief that abundant greenery in office environments is unconditionally beneficial.

According to Newsweek, the researchers developed a new method for quantifying the amount of greenery and wooden elements in interior spaces. For the experiment, they simulated conditions closely resembling those of a real office, including a hypothetical maximum — defined as 100% plant coverage, representing the highest possible number of plants in a given space.

The results were surprising: the highest stress levels among participants were observed when the workspace was filled with plants and small trees at around 60% coverage, Planet Today reported. Previous experiments typically relied on subjective assessments or compared only the presence versus the absence of greenery.

This time, new software allowed scientists to avoid such limitations. It calculated the average number of natural elements visible to a person within a defined area. Analysis of participants’ responses showed that people felt most comfortable in spaces where greenery accounted for about 20% of the possible maximum. In such an environment, individuals maintain a sense of connection with nature while avoiding excessive stress and overstimulation.