Litter is the topmost layer of soil, consisting of at least 20% dead organic matter. Decomposition (the breakdown of organic matter), alongside photosynthesis, is a key process related to the cycling of matter, elements, and energy in nature. Research on the rate of decomposition is essential for understanding the consequences of changes in plant biodiversity for ecosystem functioning. During the workshop, we will present, step by step, the litter bag method, which is commonly used in studies of the decomposition process.