Conceptions of ecological processes such as the flow of energy and cycling of matter in an ecosystem are increasingly important understandings in a rapidly changing world. This study utilizes a p-prims, or knowledge in pieces, lens to examine understandings and disconnections in students' conceptualizations of energy flow and matter cycling specific to our context. Findings from our analysis drove continued refinement of our "Compost" curriculum through modifications designed to build on students' p-prims and foster deeper understanding of ecological processes.