The salt tolerance of N. Co. 293 and N. Co. 310 was determined in large greenhouse soil cultures with four levels of added NaCl and CaCl2 and in artificially salinized field plots. In the latter, sulfate salinity and high proportions of magnesium salts were also studied. ‘N. Co. 293’ was more salt‐tolerant than ‘N. Co. 310’ at moderate and high salinities, but both varieties had similar salt tolerance in the greenhouse at a low salinity. Yields decreased by 10% at 3 mmho/cm (ECe) and by 25% at about 5 mmho/cm. The ratoon crop in the field plots was only half as salt tolerant as the seed crop, and differences in salt tolerance between the varieties diminished during the second year. The greater sensitivity of the second year's growth is tentatively attributed to the combined effect of low winter temperature and salinity.