Urban agriculture is a promising avenue for food system change; however, projects often struggle with a lack of volunteers—limiting both their immediate goals and the broader movement-building to which many alternative food initiatives (AFIs) aspire. In this paper, I adopt a case study approach focusing on Farm X, an urban farm with a strong volunteer culture located in Tāmaki-Makaurau Auckland, New Zealand’s largest city. Drawing on a significant period of researcher participation and 11 in-depth interviews with volunteers and project coordinators, (...) I first contextualise and explore the history of Farm X, then offer themes to describe key factors which help or hinder their volunteer engagement. Engagement is helped by strong leadership, learning by doing, socialising around plants, and contributing to a movement. Conversely, engagement is hindered by time scarcity, economic hurdles, and struggles over direction. Drawing on McClintock’s (Local Environ 19(2): 147–171, 2014, 10.1080/13549839.2012.752797) insights into the hybrid and contradictory nature of urban agriculture as a tool for social change, the paper continues with a discussion of two important trade-offs involved in both farm management and the movement building promoted by Farm X: focused leadership verses volunteer agency; and asking more verses less of volunteers. Finally, I suggest several avenues that may be useful for other urban agriculture projects interested in movement building. (shrink)