Growing up in a small coastal town, students spend a great deal of time outdoors and at the beach. Given the many learning opportunities that such an environment can provide, engaging students in a sustained, environmental service project seemed like a natural complement to lessons focusing on the interaction of organisms within a habitat. This experience provided opportunities for students to examine how they can improve the water quality of marshes. In the unit presented in this article, fifth-grade students planted and raised "Spartina" grass in a portable greenhouse at school, then worked with a organization to plant the seagrass in the local marsh to provide refuge for animals and help support the environment. The fifth graders learned how planting this key species can lead to a cleaner marsh.