Abstract The growth of sodium nitrate was studied in a microscopic setup; crystals were nucleated and grown from mixtures of water and isopropoxyethanol (IPE). The phase diagram of the IPE/water system saturated with sodium nitrate and the solubility of NaNO 3 in aqueous mixtures with IPE were determined. The growth rate was found to be dependent linearly on the concentration difference ( c–c ∗ ). Mass transfer constant k D decreased with increasing weight fraction of isopropoxyethanol in the mixture and was predicted accurately from density, viscosity and solubility data only. No changes in crystal morphology were observed.