In this study, we compared a traditional teaching sequence (four distinct lessons) with a block schedule dealing with the ecological adaptations of the water lily. The educational unit contained original plant material and both experimental groups received the same tasks and working sheets. Pupils worked together in groups of three to four pupils in a self-regulated manner, carrying out hands-on experiments. However, both groups differed in their time schedule (four distinct lessons of 45 min versus one block of 180 min). Pupils from the traditionally scheduled education performed significantly better in the immediate post-test while these differences merged in retention.