A filed experiment was carried out during the two successive summer seasons of 2021 and 2022 at the Experimental Farm, El-Gemmeiza, Agric Res. Station, (ARC), Gharbeya Governorate (Middle Delta, Egypt), to study the effect of the effect of planting date (15^th April and 15^th May) and potassium rates (24, 48, 72 and 96 kg K₂O/fad.)  as soil application as well as their interactions on growth, productivity potassium use efficiency and tuber roots quality of sweet potato (Beauregard cv.)  under clay soil conditions. Under clay soil conditions and during summer plantations, planting sweet potato on 15^th May and fertilizing with 72 kg K₂O/fad. in the form of potassium sulphate increased vine length, number of branches/ plant, leaf area / plant, shoot dry weight, average weight of tuber roots, yield/ plant and total yield /faddan. Faddan = 4200 m² = 0.42 hectare.