A plant a day keeps the doctor away

January 31, 2019

Employees find a workplace with plants more attractive than a space without plants. Plants increase air humidity, contribute to a positive mood, bring about more contentment among employees about their own performance, while it brings down absence caused by sick leave. Research by Wageningen Environmental Research in collaboration with Fytagoras has brought this to light. A number of companies and institutions were involved in the research (PRIVA, Noviflora, IVN, De Groene Stad, Royal FloraHolland, Donkergroen and DGBC). Today the results are presented at the congress of the Dutch Green Building Council called: Building Green, Smart and Healthy.

The costs of buying and maintaining plants will generally be recovered within one year. Primarily because of less sick leave and better performance by employees. After that, the investment in plants will actually start generating money. Plants are for example a cheap alternative way to increase air humidity in work spaces or to cool rooms in summer. These effects can be used for climate control and cuts on energy consumption.

Study design

The research was carried out at several companies and care institutions. A space at each company was provided with plants, with a comparable work place next to it without plants. Living rooms or general areas of care institutions may or may not be equipped with plants. Researchers placed sensors in both areas, to be able to determine the physical differences between the two spaces. Employees, who were working in those spaces, indicated before as well as after the introduction of the plants, their feelings about the workplace, the interior climate, the atmosphere at work, their mood, well-being and health. Focus tests were carried out and the cortisol level (a stress hormone) was determined of each participant as well.

Six positive effects

This study has revealed, that six positive effects can be linked to having plants in the work space.

1.    Air humidity: the relative humidity in spaces with plants is 5% higher on average, than in areas without plants. An improvement of even 17% was measured during winter.

2.    Thermic comfort: employees are less likely to perceive the temperature in an office space as too hot or too cold.

3.    More attractive: people found their workplace more attractive to look at after introducing plants.

4.    Mood: the mood of employees after the plants had been placed, was more positive than before. Employees from companies also tended to worry less about work during free time.

5.    Satisfaction about performance: employees are more content about their own performance after the introduction of plants than they were before having plants in the work space. This also goes for their expectation on their employer's satisfaction about this performance.

6.    Less sick leave: people who are working in a space with plants, report less sick for work. This comes down to on average 1.6 days less sick leave per employee per year.

Care institutions also participated in the research. The plants were evaluated as positive by care staff working in a living room decorated with plants. However, the impact on the interior climate as with the companies could not be indicated here. “The most important reason for this, is the limited mobility of elderly people. The doors remained open a lot of the time,” explains Tia Hermans, project leader of Wageningen Environmental Research. “Because of this, the impact the plants could have was distributed over a larger area than we had scheduled. These things can happen in a practical study.”

Follow-up research

A follow-up study will be carried out on the details of the business case of the recovery time. Tia Hermans: “We know that entrepreneurs and employers will only decide on large-scale introduction of plants, when it is a convincing business case. We are planning to set up just that business case on several locations. Like this, we want to make it more attractive to employers and also to facility services and human resources management, to invest in a green interior climate at work.”