This paper examines self-sown crops as agents in the agricultural development of Aus- tralia’s southern mallee lands from the 1890s to the 1940s. Self-sown crops suggested ways to farm and provided the enticement of an occasional windfall. They assisted with expansion and consolidation of holdings and provided moral lessons in the value of persistence. In the context of the rise of modern, scientific farming characterized by strict regimes of crop rotation and fallowing, self-sown crops encouraged farmers to maintain more adaptive, less regimented approaches. Ultimately, modernist systems triumphed, and by the mid-twentieth century self-sown crops were all but excluded from mallee agriculture. For a time, however, these plants played a significant role in shaping ap- proaches to farming in the mallee lands and sustaining agricultural enterprise there.