A fortifier for growth and flowering in horticulture, trees and ornamental plants, aromatic plants and fruit trees, from wastewater from brewer's yeast with a very low protein concentration. The method including the step of: filtered by 80 μm; magnetic treatment of the liquid; addition of 0.1 to 20 g/l phosphate and 10 to 20 g/l glycose. Fermentation is carried out keeping the free amino acid content greater than 0.1%, the content of Mg+2 greater than 0.1%, total nitrogen, phosphate, and potassium below 3.0%, the content of protein from 0.5% to 1.0% and EDTA from 0.02% to 0.2%, all by dry matter weight; addition of microbes from the environment; at temperatures of 15° C. to 40° C. with gentle agitation, for 24 hours to 30 days; subsequent filtering and pH adjustment. It has been found to be effective in various crops.