Strawberries (Fragaria × ananssa Dutch.) cv. `Aliso`, Selva`, `Gaviota` and `Camarosa`) were grown hydroponically with five ratios of NH4/NO3 (0/6 (S1), 0.25/6(S2), 0.5/6(S3), 1/6(S4), 2/6(S5)) and constant total N in three replicates for two seasons (summer: July-November, and winter: December-June) to determine the relationship between the rate of NH4/NO3 and nitrate accumulation in different plant organs. Leaf and petiole nitrate contents were measured three times each season (summer: August, September and November and winter: April, May and June). Leaf nitrate percent increased gradually. Petiole and root nitrate contents were dramatically higher than content in leaf and crown. In leaf and petiole, nitrate content increased as NH4-N increased in nutrient solution. Nitrate percent in crown and root were highest with NH4-N increasing from 0.25 to 0.5 mM were constant in the remainder solutions. Aliso had the highest crown and root nitrate. Gaviota had the highest leaf nitrate while Camarosa the highest petiole nitrate content. S2, S4 and S5 nutrient solutions resulted in highest nitrate content in petiole. Crown, root and fruit nitrate contents were highest in 0.25 mM NH4-N; increasing ammonium in solutions caused a decreasing nitrate in these organs. Nitrate content in fruit, leaf, crown and root, were highest in Gaviota. Nitrate in leaf, root, petiole, and crown, were significantly higher in summer than in winter. Based on these results, solution S5 and cv. Aliso ore suggested for commercial use both because of bearing low nitrate containing fruit
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