The effects of variations in the supplies of nitrogen, phosphorus and potassium on the appearance, growth and yield of the tinted lettuce May King have been studied by Woodman (1936, 1939a, b, c, d). The present experiments were designed: (i) to test the main findings of the previous experiments in a comprehensive experiment, (ii) to discover how far certain deficiency symptoms noticed in May King were common to a non‐tinted lettuce, and, (iii) and (iv), to ascertain what effects variations in the supply of calcium and magnesium respectively had on sand cultures of lettuc