For effective deliveries of nutrients to plant species, we have studied release profiles of KCl, NH4NO3, KNO3, (NH4)(2)SO4, and K2SO4 as fertilizer substrates. The effect of coating the fertilizers with paraffin wax or a mixture of paraffin wax and rosin and the effect of temperature (25, 30, and 35 degrees C) were explored. The dissolution rate and ultimate amounts dissolved were in the order of KCl > NH4NO3 > KNO3 > (NH4)(2)SO4 > K2SO4. The order was unchanged whether the fertilizers were coated or not. Coating with paraffin wax exhibited ultimate amounts dissolved lower than those of uncoated samples. Wax/rosin-coated samples attained dissolutions similar to those of uncoated samples but at slower rate. The results showed wax/rosin coating to be more effective than wax-only coating, but the difference diminished for low dissolving fertilizer such as K2SO4. When wax-coated samples were tested at 25, 30, and 35 degrees C, the rate of dissolution increased but the order of the ultimate amount dissolved was unchanged. As the temperature was increased, the range of the ultimate amounts dissolved between KCl and K2SO4 narrowed. The ranges are 0.09, 0.07, and 0.06 mol/dm(3) for 25, 30, and 35 degrees C, respectively.