The purpose of the notification is to stimulate the growth and development of plants on the basis of hydrolysates of protein raw materials of natural origin, i n particular keratin,in the form of an aqueous solution or a powder to be dissolved in water. The stimulator contains 1 -99% mass,favourable 50-75% mass. in the water-soluble mass of the mixture of amino acids which are the product of the combination at a time. below 65oC, the first protein hydrolysis resulting from the acid hydrolysis of natural substances containing keratin with the second protein hydrolysis resulting from the basic hydrolysis process of natural substances containing keratin,with respect to the first to the second hydrolysis from 1:1 to 1:20, which is a hydrolysate combination operation, is carried out before mixing amino acids with a solution containing the hydrogen soluble salt of at least one macro and/or micro-elements such as: nitrogen in quantities 0,1 to 40% mass.phosphorus converted to P2O5 in 0,1 to 40% mass,potassium converted to K2O in quantities 0,1 to 40% mass,magnesium converted to MgO in quantities of 0,1 to 40% masses,calcium converted to CaO in quantities 0,1 to 30% mass,sulphur converted into SO3 in quantities 0,1 to 40% mass,boron in quantities 0,01 to 25% mass,copper in quantities 0,01 to 25% mass,iron in quantities 0,01 to 25% mass,manganese in quantities 0,01 to 25% mass,molybdenum in quantities 0001 to 15% mass,zinc in quantities 0,01 to 25% mass, cobalt in quantities 0001 to 10% mass,or is carried out in a solution containing hydrogen-soluble sulphate salt of at least one of the elements of Zn, Cu, Mg, Fe, Mn, and that the combination of amino acids with macro and/or micro-elements is favourably carried out in the presence of at least one compound of the groups comprising polysaccharides, polyalcohols, acids humus and fulminate, citric acid, ascorbic acid, ethylenediaminotetracoic acid, with the pH of the stimulator being 2 to 12, and preferably 4 to 8, and preferabl
