Virginia I. Lohr and Caroline H. Pearson-Mims 
Dept. of Horticulture and Landscape Architecture 
Washington State University 

Impact of interior plants on human stress and productivity

Computer lab without plantsComputer lab with plants
This study was conducted in a computer lab at Washington State University.  Subjects asked to participate in an experiment to measure stress levels in people using computers.  Subjects were randomly assigned to be tested in the computer lab when plants were absent or when they were present.  Interior plants, when present, were placed around the sides of the room. Subjects' blood pressure and emotions were monitored while they performed a slightly stressful computer task that measured reaction times in response to seeing and decoding the shape of a simple object on the screen. 

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. 

The following article discusses this research, which was partially supported by the American Floral Endowment and the Horticultural Research Institute

Lohr, V.I., C.H. Pearson-Mims, and G.K. Goodwin. 1996. Interior plants may improve worker productivity and reduce stress in a windowless environment.  J. of Environmental Horticulture 14(2):97-100. 

Virginia Lohr (E-mail:
Caroline H. Pearson-Mims (E-mail:
Department of Horticulture and Landscape Architecture
Washington State University
Pullman, Washington 99164-6414 U.S.A.

Updated May 30, 2001