Transdisciplinary learning environments have potential to bring together the arts, sciences, and computing within schools. We investigate the student and teacher enactment of sensemaking practices that break down disciplinary silos. We describe a pedagogical approach, Luminous Science, where students make dynamic, computationally-rich artistic representations of data from a classroom garden. Then we present an analysis of students' sensemaking practices used during the transdisciplinary unit in three cases of art, science and computing classrooms. Qualitative analysis of a student group and teachers' curricular materials in each of these classrooms elucidates how teachers' enactment choices, organization, and facilitation of the unit we co-designed with them facilitated opportunities for students' transdisciplinary thinking and learning. We show that when teachers' enactments supported increased computational complexity and ties between artifact and phenomenon, then students participated in deeper transdisciplinary sensemaking. We discuss the implications for the design of curricular materials and professional development to support effective organization and discourse practices by teachers in orchestrating transdisciplinary sensemaking.