A pot experiment was carried out with strawberry (Fragaria x ananassa Duch) cvv. Oso Grande and Camarosa in sand culture to investigate the effects of foliar application of 4 mM KH2PO4 to plants grown both at high NaCl concentration (35 mM) supplied via roots and in complete nutrient solution. Treatments were (1) nutrient solution (C); (2) nutrient solution + 4 mM KH2PO4 as a foliar application (C+Fo); (3) nutrient solution + 35 mM NaCl (C+S); and (4) nutrient solution + 35 mM sodium chloride + 4 mM KH2PO4 as a foliar application twice weekly (C+S+Fo). The plants grown at high NaCl had less dry matter, fruit yield, and chlorophyll content than those grown in normal nutrient solution for both cultivars. Foliar KH2PO4 sprays ameliorated the negative effects of salinity on plant growth and fruit yield. Water use by plants decreased with elevated NaCl and increased with foliar KH2PO4 sprays. Membrane permeability increased with high NaCl and was reduced by KH2PO4 sprays. Sodium concentration in plant tissues increased in both cultivars in the high NaCl treatment. Concentrations of P and K were in the deficient range in plants grown at high NaCl and these deficiencies were corrected by foliar KH2PO4.