Echoing calls to expand environmental education research through design, this study explores the role of design in garden-based education and illustrate its contributions towards practical impact and theoretical insight. Design can explicate and map conjectures about resources, tasks, roles, and other supports for learning and teaching then, in turn, can be teste to illuminate how these supports operate together. Design, as such, focuses holistically on examining systems of activity. To these ends, case study method organizes analysis of garden-based learning in a US fifth-grade classroom (ages 10-11) that enacted a project-based gardening curriculum. Findings develop threes themes about designed supports: relating content and context; aligning curricula and gardens; and designing for curiosity and wonder. Discussion considers the role design plays in organizing, enhancing, and ultimately growing garden-based learning as well teaching and learning in environmental education more broadly.