A new study by Stanford University researchers has found that while a few indoor plants can make people feel calmer and more connected, too many plants might actually lead to stress.
The study, published recently and reported by Newsweek, challenges the long-held belief that more greenery automatically creates a better mood. Researchers discovered that there is a “sweet spot” when it comes to how much nature we should bring indoors.
Balancing Nature Indoors
The research team developed a new method to measure how much greenery and wood materials people are exposed to in enclosed spaces. Using this approach, they designed virtual office environments with varying levels of “indoor nature” — including potted plants, wooden furniture, and window views of trees — to see how each affected participants’ wellbeing.
The results revealed that a moderate amount of plants—such as a few potted greens and a natural outdoor view—helped participants feel more relaxed. However, when around 60 percent of the virtual room was filled with plants and wood, stress levels noticeably increased.
Study author Eva Bianchi, a civil engineer at Stanford, said the results went against initial expectations.
“We assumed that more natural elements would always be better. But our findings show that too much nature indoors can actually make people feel overwhelmed,” she explained.
How the Experiment Worked
The researchers created 11 digital conference rooms with different combinations of plants, wood, and outdoor nature views. Using 3D modelling software called “Nature View Potential”, they precisely calculated how much natural material each participant could see in their virtual environment.
A total of 412 participants took part in the study. Each was asked to imagine that the virtual room was their new workplace before performing mild stress-inducing tasks—such as solving difficult word puzzles or counting backwards in increments of 13 from 1,022.
Contradicting Past Studies
Previous research has consistently suggested that indoor plants reduce stress and boost productivity, but most of those studies compared only rooms with and without plants, not varying levels of greenery.
Co-author Professor Sarah Billington explained that inconsistent methodologies have made it hard to compare results across studies.
“There’s been a lot of research on the benefits of plants indoors, but because of different approaches, we couldn’t really measure how much nature is ideal,” she said.
The Stanford team’s findings suggest that while some greenery enhances mental wellbeing, too much can be visually cluttering and trigger stress rather than relaxation.
Takeaway
The researchers concluded that balance is key — a few natural touches like potted plants or wood textures can foster calmness and focus, but overloading a space with greenery may backfire.
So, for your home or office, the advice is simple:
✅ Keep it green — but not too green.