A method for making products used in micronutrition which includes selecting for at least two among the following types: trace element, plant, food principle, microorganism, vitamin, one or several active substances of each type depending on the functions required for the system; sequentially combining the active substances of each type by introducing sequentially each of them in an intermediate container in the form of a liquid solution, so as to obtain a partial solution; and combining sequentially and in the following order: trace element, plant, food principle, microorganism, vitamin, the resulting partial solutions by introducing sequentially each partial solution into a final container.