This dissertation examines how pedagogies of sustainability are embedded in socio-cultural contexts and policy structures and driven by the localized actions of teachers. Through a comparative case study in two cities with extensive and varied school garden programs, Havana and Philadelphia, this dissertation analyzes the roles, understandings, and implementation processes of teachers. First, in both Philadelphia and Havana garden educators draw on pedagogical frameworks about what, where, and how students should learn as "gateways" to navigating barriers and promoting garden education, though the character of these frameworks reflects particular context. Second, concerns educators identify related to students' nutritional health and particular social conditions--hunger in Philadelphia and vulnerability to food insecurity in Havana--shape the pedagogical intentions and social meanings of school garden programs in both cities. Lastly, for teachers in Philadelphia and Havana, garden education is a source and a mechanism for personal, social, and ecological regeneration in schools and communities. While Philadelphia educators see this regeneration catalyzed by and reflected in the transformation of formerly degraded school yards to spaces of natural beauty, Havana educators concentrate on the transformative power of students' engagement in collective garden labor to cultivate a "culture of nature." With these findings, this study is a theoretically and practically salient comparison of the dynamic interplay between the social context of policy, educative programs aimed at sustainability and eco-social engagement, and local actions of teachers. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]