Two seasons (2005/06 and 2006/07) of field experiments which aimed to study the suitability of new and established husked oat varieties, variety mixtures and a husked oat population for organic systems were established at two sites in the west and east of the UK. The ground cover and leaf area indices of the varieties had significant effects on final yields in the 2005/06. Mixtures generally yielded similarly to the means of component varieties but the mixtures in 2005/06 and 2006/07 had 25% and 18% less disease, respectively, than the average of the component varieties at one site.