This experiment was carried out during the two seasons of 2019 and 2020 to study the effect of potassium humate as soil application at different concentrations 1.5, 3.0, 4.5, and 6.0 g/vine on vegetative growth, nutrient content in leaf petioles, yield and berries quality of ‘Red Roumi' grapevines grown in clay soil in a private farm at Sambokht, Gharbia Governorate, Egypt. Obtained results indicated that adding K-humate at the rate of 6.0 or 4.5 g/vine enhanced vegetative growth, leaf mineral content, yield, and berry physical and chemical qualities as compared with the other treatments. Furthermore, the application of 6.0 g/vine produced the highest significant values of yield per vine or per feddan, SSC per vine, cluster and berry weight, total anthocyanin content in berry skin, and total carbohydrates and proteins in canes compared to other treatments used in both tested seasons.