seed–people relationships date back millennia but have been dramatically reorganized in the last 100 years. this reorganization is just one part of the vast array of interconnected factors that together have led to the entrenchment and domination of the current industrial food system. this food system, in turn, is a major driver of global environmental degradation. the results of the ongoing accelerating deterioration of the health of the planet have profound consequences for the health of all beings that live upon it. while much research has been done exploring the role of food systems in influencing the health of both people and planet, less is understood about the role that seeds play. landrace seed breeding is a traditional form of seed–people relationship in which both are understood to be engaged in a co-evolutionary process of adaptation. in contrast to modern seed–people relationships in which seeds have been commodified and privatized, landrace breeding is understood to be a collaboration between seeds and people. this thesis considers the ways in which landrace seed breeding is connected with an eco-social approach to health through the exploration of the relationships that exist between seeds and people within the context of an ongoing landrace breeding project in ontario, canada. rooted in posthuman and assemblage theory, and employing posthuman methodologies, this study takes the shape of a multispecies ethnography in which seven humans and five landrace populations of watermelon participated. this research found that the relationships between growers and watermelons created a unique space from which a re-orientation of worldviews, new perspectives, and new stories about how humans relate with other species could emerge. in light of the ongoing calls for new ways of knowing and doing by those seeking to address the growing challenge of supporting health from an eco-social perspective, this research suggests that landrace seed breeding may be of importance beyond the agronomic benefits it is known to provide. this research also exemplifies the relevance and utility of posthuman and assemblage thinking (as both theory and research methodology) in facilitating a reimagining of the world around us and the place and role of humans within it.