The Ca intake by plants, grown in sand, and water cultures of varying combinations of nitrate and ammoniacal N and containing equal amounts of the most essential elements, was increased in direct proportion to increments of nitrate over ammoniacal N supplied by the nutrient solution. The sand cultures received N as follows: all, 3/4, 1/2, 1/4, and none as nitrate with the balance made up with ammoniacal N. The Ca contents of the respective plants were 3.48, 2.37, 1.45, 0.98, and 0.65%. One set of water cultures received all nitrate while another received all ammoniacal N. Ca was 1.79 and 0.62%, respectively. The tests were repeated 3 times in duplicate and an average Ca content was presented.