Two field experiments were conducted during the two successive winter seasons of 2017/2018 and 2018/2019 at Tag Al-Ezz Agricultural Research Station, Agricultural Research Center, Dakahlia Governorate, Egypt to study the effect of foliar spraying of some potassium sources i.e. potassium silicate at 4ml L^-1, potassium humate at 4ml L^-1 and a mixture of them as main plots and foliar spraying with four levels of boron (0.0, 100, 150 and 200 mgL^-1) as sub plots as well as their interactions on nutrients concentrations, yield components, quality characters and yield of sugar beet (Beta valgaris var. saccharifera L. Faten variety). The experimental design was split-plot design system. Spraying sugar beet plants with a mixture of K-Silicate and K-Humate produced the highest values of all studied parameters i.e. NPK concentrations, yield components, quality characteristics and yields followed by spraying with K- Humate, then spraying with K- Silicate and control in a descending order, with exception juice purity that had inverse trend in both seasons. Spraying sugar beet plants with a solution of boron at a rate of 100 mgL^-1 was more effective than other studied boron levels in increasing nutrients concentrations, yield components, quality characters and yields and gave the highest values of them during both seasons. It can be concluded that maximum sugar beet nutrients concentrations, yield components, quality characters and yields were significantly affected by the interactions between the foliar spraying of K-Silicate+K-Humate mixture and boron at a rate of 100 mgL^-1 under the environmental conditions of Dakahlia Governorate, Egypt.