Sulfate of Potash has long been recognized as a premium source of both potassium and sulfur due to its dual nutrient status, lack of chlorides and low salt index which provides for greater crop safety. However, Sulfate of Potash (SOP) has not been able to fully participate in the liquid fertilizer industry due to its low solubility relative to other, non-chloride potassium sources. ESP(TM) K-Sulfate is a newly developed form of SOP with enhanced solubility making it suitable as an effective potassium source for solutions used in foliar cotton applications. ESP requires heated water to initiate its enhanced solubility, but will resist salt-out as the solution cools; once cooled to ambient temperatures above 60 degrees Fahrenheit, no salt-out will occur during long-term solution storage. ESP solutions will also resist salt-out at temperatures down to 30 degrees Fahrenheit when combined with certain nitrogen sources. ESP solutions have been made to grades of up to 0-0-8.5% K20 and various nitrogen sources have been found to be compatible in making grades such as 3-0-6 (Urea), 6-0-7 (UAN), and 4-0-6 (Triazone). Solutions made with ESP(TM) K-Sulfate have a lower salt content than solutions made with either potassium chloride (KCI), potassium nitrate (KNO3), or potassium thiosulfate (K2S203), and so represent safer foliar solutions, particularly under conditions of plant stress. ESP solutions have been used by five large liquid fertilizer dealers in a limited test market begun in April, 1993, and only calcium nitrate and neutral pH phosphorus have shown some incompatibilities; no incompatibility has been observed with insecticides, but additional compatibility tests with pesticides are needed. ESP based solutions mixed with insecticides have been successfully applied as a foliar spray to cotton via boom spray, and have been flown on crops via aerial application.