Could used coffee grounds be good for your plants? University of Haifa scientists are planning to answer that question.

Researchers at the Kadas Green Roofs Ecology Research Center, operating under the Faculty of Natural Sciences’ Institute of Evolution, and working in conjunction with the Student Union and the Green Campus project, are using the waste from coffee machines to fertilize an experimental plot in which different species of vegetation have been planted. The purpose of the research is to determine not just if coffee can be part of a substrate suitable for growing plants, but whether it might be even better than a normal substrate and will enhance the plants’ growth.

“At our research center we have a number of studies going that are examining what quality of the substrate and types of plants would be most suited for use on green roofs even with little or no maintenance. Using coffee waste is liable to improve the mix of minerals in the soil, and as a result, also improve plant growth on the roof,” said Dr. Shay Levy, the center’s manager.

The use of organic waste as a platform for ecological farming is already known, but despite the prevalence of used coffee (which can be taken from any coffeemaker or espresso machine), to date no one has examined its effectiveness as a green roof fertilizer. The idea was the brainchild of Prof. Shai Linn, the dean of the Faculty of Social Welfare and Health Sciences and a member of the University’s Green Campus council. Linn saw the combination of coffee waste and the Green Roofs Research Center, which is headed by Prof. Leon Blaustein and seeks to benefit the environment by growing things on the roofs of buildings, as a natural one.

To conduct this study the Student Union “donated” 17 kilograms of coffee waste from the café it runs, which was mixed with the substrate that until now has been used on the experimental plots. The plots were sown with Maltese Cross Ricotia, hare’s tail, scilla, daffodils, and even herbs like hyssop, sage, and druce. Given that rain has already fallen it will soon be clear whether coffee does roof plants any good.

“This is a great way to turn waste into a resource,” said Dr. Levy. “There’s no lack of coffee waste; on the contrary, we have more than enough of it. If we can prove that the coffee improves plant growth, it could be an amazingly ecological and economical solution for us and for the environment.”

(YWN – Israel Desk, Jerusalem)