A keratin fertilizer with humic acids in a colloid form additive, the keratin fertilizer comprising feathers having a weight, 15-18 weight % of caustic potash (KOH) with respect to the weight of the feathers, a minimum of 27.5 weight % of water with respect to the weight of the feathers, 15-18 weight % of a 85% phosphoric acid H3PO4 with respect to the weight of the feathers, 10-13 weight % of epsom salt MgSO4 with respect to the weight of the feathers, 0.19-0.23 weight % of vitriol of iron FeSO4 with respect to the weight of the feathers, 0.05-0.075 weight % of bromic acid H3BO3 with respect to the weight of the feathers, 0.03-0.055 weight % of manganic sulphate MnSO4 with respect to the weight of the feathers, 0.008-0.02 weight % of zinc sulphate ZnSO4 with respect to the weight of the feathers, 0.008-0.02 weight % of cuprous sulphate CuSO4 with respect to the weight of the feathers, 0.001-0.005 weight % of ammonium molybdate (NH4)6Mo7O24 with respect to the weight of the feathers, 17-22 weight % of calcium nitrate Ca(NO3)2 with respect to the weight of the feathers, 10-15 weight % of humic acids with respect to the weight of the feathers.