Some attention has already been given to the importance of mineral nutrition (nitrogen and potassium) in perturbing artemisinin production (Ferreira, 2007; Ferreira et al., 2007). Given the importance of nitrogen in influencing plant biomass production, and of potassium on growth through its role in the regulation of carbohydrate and protein synthesis, it is critically important that we understand clearly how best to maximize biomass production against leaf artemisinin concentration to achieve optimal yield per plant of the active component. The aims of this experiment are to describe how artemisinin yield can be optimized through nitrogen and potassium nutrition when grown in the UK.