There is substantial optimism for urban agriculture as a form of alternative agriculture that can enhance the food security of individuals within our food system. However, productivity and efficiency of this form of agriculture are not well understood in the literature. This research is the result of a case study of Guelph where fifty gardeners were selected and asked to complete a garden diary in which they recorded their production and input costs (land, labour and capital). The results indicate that the average vegetable gardener in Guelph is not able to achieve high yields but their inputs of labour and capital are quite high. Further investigation of motivations and barriers found that production was not a major motivation for vegetable gardening, but that there were numerous other benefits involved. This suggests that backyard gardening is not a viable food security strategy.