Indoor plants have their set place in many flats, offices and companies. People intuitively feel that the contact to plants and nature have a calming effect on them. Many are also of the opinion that productivity and satisfaction of workers increases, if the place of work has indoor plants incorporated. Up until now there was no scientific proof of this assumption, but now the assumption has been supported by a study carried out by the Washington State University. Ever since urbanisation, we spend more time indoors - over 90 per cent - for example in the office and at home. The indoor climate is of eminent importance for our health and our well-being. Above this: when our work becomes technically more complex, the amount of illnesses caused by stress increases. Due to this fact it is important and sensible to study the relationship between plants and the well-being of humans. Up until now there were only definite studies that underlined the above mentioned assumptions that plants are good for a healthy indoor climate and increase the well-being and the productivity of work. In early studies, that measured the effects of plants by measuring employees' blood pressure, the test persons were shown videos of plants in their natural environment. The result: the test persons, that were put under stress and that were shown plants, lessened stress faster than those who had a view onto concrete and walls.
New scientific results
A study, carried out in 1995 by the faculty of Horticulture and Landscape Architecture of the Washington State University and led by Dr. Virginia Lohr, on the effects of indoor plants on the office climate and the well-being of employees, proved that indoor plants in offices for one reduce stress and for the other helped to increase productivity. In this experiment the blood pressure, the heart frequency and the emotional condition of 96 test persons - mainly young men and women - was controlled. The students, but also the employees of the university were in a computer room with bare walls and no daylight for the duration of the test. All test persons were experienced in the running of computers. 81 per cent of the test persons answered that they liked plants; the rest had either no opinion or did not like plants. 66 per cent had plants at home or in the office.
Plants and productivity at work
Another factor decisively contributes to productivity at work: the speed of reaction. In order to be able to measure this by the test persons, a special computer programme was designed for the study, which created stress by the test persons and at the same time measured productivity. Such measurements of the speed of reaction by which test persons had multiple choice options, gave a clear picture about the mental complex functioning. For this reason they are valid as suitable means of measurement for the testing of productivity under stress, respectively tiring, conditions. The programme shows a picture on the screen selected from a range of three pictures. The test persons were told to press the key respective to the picture as soon as they had recognised the picture.
The test persons were to complete the computer tasks in two different situations: with and without plants. The plants were integrated into the test rooms in such a manner that they were visible for all test persons without distracting them from their task. After the experiment the measurements of test persons were compared with both situations. The results were clear: people in the rooms with plants were of the opinion to have been more attentive and they felt that they had worked at a more concentrated level. This in contradiction to those who did not have plants surrounding them. The test persons that carried out the test surrounded by plants, had a lower blood pressure which again is a clear sign for a decrease in stress.
"Yes" to plants
The presence or non-presence of plants, so the study shows, had no influence on the amount of mistakes made by the test persons. Both groups in rooms with and without plants, made about the same amount of mistakes. Whereby the speed of reaction of the participants that were in rooms with plants, was 12 per cent higher. Due to these results the scientists came to the conclusion that a place of work with integrated plants leads to higher productivity.