Two field experiments were carried out at El-Gemmeiza Agricultural Research Station, El-Gharbia Governorate, Egypt during 2019 and 2020 seasons, to evaluate the effect of foliar feeding with three sources of potassium [1- mineral source (potassium sulphate), 2- organic source (potassium humate) and 3- natural source (potassium ore)]at two levels from each source (0.5 and 1g/L), (2 and 4 g/L) and (4 and 8 g/L) in respective order. The effect of combination between the three sources at the two levels, in addition to the control treatment were also evaluated on growth, some physiological aspects and productivity of Egyptian cotton cultivar Giza 86. The obtained results indicated that foliar feeding with the combination of the three sources examined at the low level or at the high level resulted in significant increase in leaves N, P, K, Mg and photosynthetic pigments contents, growth parameters, earliness measurements (except boll shedding percentage which was decreased) and seed cotton yield feddan^-1, boll weight and open bolls numberplant^-1 in 2019 and 2020 seasons as well as seed index, lint%, fiber length, micronaire reading and fiber strength in 2020 season as compared with the control. It was recommended to spraying combination of the three examined K sources (potassium sulphate, potassium humate and potassium ore) at the low level (0.5, 2 and 4 g/L) in respective order three times as alternative to soil K fertilization to reduce cost, overcome K fixation and obtain high cotton productivity under conditions similar to that of El-Gemmeiza region.