Pot experiments were conducted to determine effects of applied N on NO3‐N and total N concentrations in Swiss chard (Beta vulgarisvar. cicla) and of applied N, P, and K on Bloomsdale spinach(Spinacia oleraceaL.) and on curly mustard (Brassica pervirdisL.). Ammonium nitrate produced greater increases in NO3‐N and total N concentrations in chard than did sulfur‐coated urea at the same rates of applied N. Both N and K increased yields and NO3‐N accumulation in spinach and mustard; response to applied P resulted only in decreased NO3‐N. Both total and NO3‐N concentrations decreased with dilution and/or assimilation associated with time of growth and higher yields.