The present investigation was carried out during three successive seasons (2013 & 2014 and 2015) (the first season was considered as a preliminary trial) in a private vineyard of Thompson seedless grapevines at El-deer village, Aga, Dakahlia Governorate, Egypt. The vines were 13-years old in a clay soil under surface irrigation system. The vines were trained on three wires system and cane-pruned. The aim of study was to evaluate the possibility of decreasing the amount of mineral potassium fertilizer by using various sources of organic and natural fertilizers. Plant compost and rock-feldspar were used as sources of organic and natural fertilizers either individual or mixed with mineral potassium on the basis content of potassium in plant compost and rock-feldspar. Data revealed that possibility of using organic and natural fertilizers as a partial replacement of mineral potassium fertilizer. This investigation showed that application of 60% mineral potassium fertilizer combined with 40% of (plant compost + rock-feldspar) had significant increased of shoot length, leaf surface area, total chlorophyll in leaves, leaf mineral content (N, P, K and Mg), yield, cluster weight and 100 berry weight. Also, enhanced chemicals properties of berries and total carbohydrates in canes as well as decreased the production cost and gave the best net profit/ feddan of Thompson seedless grapevines.