How much can buried tea bags teach us about soil and the climate? A lot! In the Tea Tales project, VA (Public & Science), together with researchers at Umeå University, the Swedish University of Agricultural Sciences (SLU) and the Rural Economy and Agricultural Societies, will develop a new tool to support teaching and evidence-based decision making.

The Tea Bag Index (TBI) is a way of measuring the soil’s ability to break down organic matter. The method is simple: You simply bury tea bags in the ground, leave them for a few months, and then dig them up again. By weighing the tea bags before and after they have been in the ground, it is possible to draw conclusions about the decomposition rate (in this case of both green and red tea) in a particular location.

Over the last ten years, the researchers who developed the TBI method have been enlisting the help of thousands of school pupils and other volunteers to bury tea bags in various places all around the world (see, for example, the 2015 Swedish Researchers’ Night (ForskarFredag) mass experiment – the Tea Bag Experiment). Based on the findings, the researchers created a global map of soil decomposition (the Global Tea Bag Index). As part of this new project, Tea Tales, the map will be developed into a powerful tool that farmers, gardeners and policy makers can use to obtain information about soil health and make evidence-based decisions on how to best use and take care of the land. The tool will also be able to be used by teachers in the classroom.

The tool and associated website will be developed in close collaboration with teachers, farmers and gardeners. A lesson plan and short film clips in which people will share their experiences of participating in the tea bag experiment and stories about soil health will also be created.

Tea Tales will run from December 2021 to August 2023 and is a collaboration between Umeå University, the Swedish University of Agricultural Sciences (SLU), the Rural Economy and Agricultural Societies (Hushållningssällskapet) and the non-profit organisation VA (Public & Science). The project is funded by Formas.


For more information, please contact David Borgström , Project Manager at VA (Public & Science)