In the face of a dire food security challenge in South Africa, high food price spikes in 2008 revitalised a governmental emphasis on the value of urban agricultural responses, especially at the local and household level. Limited empirical evidence casts doubt on this as a suitable response. This paper fills that gap to some extent and confirms a modest impact of an urban agriculture-based programme implemented by the former Gauteng Department of Agriculture, Conservation, and Environment, which established community gardens for the poorest of the poor. Prior reviews finding modest impacts elsewhere have lead to a polarised academic literature, criticism of urban agriculture as a response to food insecurity and development at large contrasts widespread advocacy. In this paper, a new insight is gleaned by opening up the implementation of ‘black box’ to reconfigure the polarised debate thus far. In one sense, the findings reiterate the potential but ambiguous and modest benefits of urban agriculture as a response to the complex food-insecurity problem due to government systems and processes. The implementation of community-based programmes, if pursued further, requires far greater institutional integration and contextual backing, especially considering a more sophisticated understanding of urban food systems. For example, the blurring between income-based and subsistence rationales within programme and policy provisions frustrate the overall success of community gardening, with implementation processes failing to achieve either. Gardens therefore fail to find a niche within wider systems of production, marketing and availability, or as safety nets and social protection. In another sense, the discussion suggests a more critical review of the continuing (misplaced) discursive biases of urban agriculture within policy and practice. This means that although there is more to be researched in terms of the ‘practice of urban agriculture’ and its implementation in specific contexts, we cannot forego critical evaluation of (discursive) policy dynamics, their institutional effects and their manifest praxis.