In this article we analyze preschool teacher students' conversations on planning teaching for sustainable development; a project. Previous research shows that teaching situations often involve strategies of achieving behavioral change; i.e. teaching the right way to handle garbage, and less activities allowing children to value and critically discuss sustainability issues. We take a pragmatic theoretical perspective to identify discourses on didactic choices created by teacher students during seminars. Texts in the form of transcripts of audio recordings from three seminars were analyzed, with the purpose of determining what didactical dilemmas were created in the students' discussions and in their reasoning about how to solve them. The results show a didactic dilemma common among the five groups of students. A tension between content as given, based on the curriculum, and content as created, based on children's experiences and ideas. Furthermore, the teacher students verbalized a third way of handling content, involving oscillating between given and created content. This oscillation allowed them to avoid normative teaching and instead achieve pluralistic teaching. Pluralistic teaching does not exclude predefined content such as facts, but it also includes other knowledge sources as well as allowing children to form their own opinions about sustainability issues.