Complex equipment for crystal growth in the dynamic regime was used to measure simultaneously the growth kinetics of three large KDP crystals at around 55°C, in ∼ 9 of solution at pH = 4.7. The same pattern of evolution was recorded for the prismatic faces of all crystals. The (heterogenous) nucleation mechanism of growth changed to a dislocntion mechanism at σ 7% and a @'dead@' growth zone was found at σ < 1.2-1.4%. The edge free energy was estimated as γ/kT 0.4 in the nucleation region. In the transient region σ 1.2-2.0%, a retardation effect due to impurities is suggested.