This study was conducted at El-Gemmeiza Agric. Res. Station, Gharbeya Governorate, Egypt, over the course of two consecutive winter seasons in 2021/2022 and 2022/2023. The aim was to assess how the potato plants responded to different potassium levels (48, 72, and 96 kg K2O/fad.) and sources such as foliar spraying (applying potassium nitrate, potassium citrate, and potassium silicate), in addition to unsprayed treatment (control), and their interactions with respect to growth, productivity and tuber quality, when grown in clay soil using a furrow irrigation system. Fertilizing potato mondial cultivar grown in clay soil during winter plantations with K₂O at 96 kg /fad. (100 % of the recommended rate) and foliar spray with potassium nitrate at 2.39 g /l followed by fertilizing with the same rate of K₂O and foliar spray with potassium citrate at 2 g /l increased plant height, number of main stems, number of leaves, total chlorophyll, tubers number / plant, weight of tuber, yield / plant and total yield /fad. and efficiency of potassium use, N contents in tubers. The combination between K₂O at 96 kg /fad. and foliar spray with spraying with potassium citrate increased P content in tuber. While, dry weight of shoots/plant, potassium content, dry matter and starch contents in tubers at harvesting date were the highest with the combination between K₂O at 96 kg /fad. and silicate potassium at 9.16 ml/l as foliar spray in the two seasons.