Flax plants were grown in growth chamber studies using 16 soils in two experiments to examine the effect of soil Ca, Mg, Zn, P, pH and conductance on flax yield and nutrient content and to identify which of these soil characteristics would be most useful in predicting the potential for Zn deficiencies in flax. Dry matter yield increased as Zn content of the soils increased and decreased as Mg content of the soil increased. Availability of P to flax increased with increasing Zn level in the soil and decreased with increasing soil Mg and pH. Availability of Zn to the plant increased as soil levels of Zn, P and the Zn/P ratio increased and decreased as soil Mg, pH and conductance increased. Deficiencies of Zn for flax production appear most likely to occur on soils that have a low Zn and Zn/P ratio and high levels of Mg, pH and conductance.