Water containing 3.6, 7.2, or 10.8 mmol N/L and uniformly supplied with 2.0 and 5.0 mmol/L of P and K, respectively, was used for irrigating greenhouse‐grown French beans (Phaseolus vulqariscv. ‘Blue Lake'). The fertilizers were applied with every irrigation via the irrigation stream. The plants were grown in pots, each filled with 12 kg of soil. In all treatments a 0.3 leaching fraction was allowed. The total amounts of N applied in a total amount of 180 L water per pot were 9, 18, and 27 g/pot for the three N levels, respectively.