Twenty sweet corn tissue samplings were made from ten field trials during 1974–76. Fertilization had little effect on yields, but a good relationship was found between yields and leaf tissue nitrate and potassium concentrations, in the leaves 40–50 percent developed at the F‐9, F‐13 and F‐14 vegetative stages. The lower and upper tissue nitrate and potassium concentration limits (deficiency and excess) were found to range between 2000 and 3000 ppm nitrate, and 1.5 and 4.2 percent, or 2.0 and 3.25 percent potassium, according to their vegetative development. Excessive nitrogen and phosphorus application decreased kernel tenderness and total solids (sugar) content, but potassium fertilization enhanced total sugar accumulation.