Is that woman banging on about plants again? Anyone who has sat in on one of my presentations or browsed my website will know that I passionately believe in the health and 'wellbeing' benefits delivered by plants around the home and the workplace. This belief comes from my interest in Feng Shui and from practical experience. Well, in April an expert in environmental psychology has put her seal of approval on the subject.

Dr Tina Bringslimark of the Agricultural University of Norway and Terry Hartig, Associate Professor in Applied Psychology, Institute for Housing and Urban Research have just published a paper "Psychological Benefits of Indoor Plants in Workplaces".

They were following up previous lab experiments and studies that had documented beneficial effects of plants on 'psycho-pysiological' stress, task performance and symptoms of ill health.

Together, Bringlismark and Hartig observed nearly 400 office workers in three offices, with different amounts of greenery. "We investigated the amount of self-reported sick leave there was and compared it with the amount of plants they could see from their desk. The more plants they could see, then the less self-reported sick leave there was."

The research was very robust, taking into account other factors such as noise, temperature, lighting and air quality (all subjects close to the heart of Feng Shui practitioners, by the way). After allowing for these other factors they found, quote: "Reliable associations with sick leave and productivity... Such associations can have substantial practical significance over large numbers of office workers over time."

 When plants were added to the lab, the subjects were more productive (12% quicker reactions on the computer task) and less stressed (systolic blood pressure lower).  They also reported feeling more attentive when the plants were present.