This paper will be of interest to agriculturalists, researchers and fieldworkers, and those working at the community and project level. It notes several misconceptions which limit researchers in their investigation of local knowledge concerning crop health. Farmers have many ways to assess and influence the health of a crop without explaining it in terms of a disease. It may often be useful to carry out a parallel study of the analytical principles in understanding personal health within the community, as this will shed light on health in the plant world. Explanations also need to be considered in association with different socio-political contexts. The paper warns against the use of formal methodologies and data collection tools, as they are seen as being inappropriate in the context of learning how farmers understand crop health. It is also seen as important to look as much at variations in the production system as it is at the norm. Indeed, the paper warns against any notion of the norm. Finally, it is also suggested that researchers be careful to avoid choosing informants who have a high profile in terms of their perceived farming skills.