An composition comprising: (A) a mixture comprising at least one (thio)phosphoric acid triamide according to the general formula (I) R1R2N—P(X)(NH2)2, wherein X is oxygen or sulfur; R1 is a C1 to C20 alkyl, C3 to C20 cycloalkyl, C6 to C20 aryl, or dialkylaminocarbonyl group; R2 is H, or R1 and R2 together with the nitrogen atom linking them define a 5- or 6-membered saturated or unsaturated heterocyclic radical, which optionally comprises 1 or 2 further heteroatoms selected from the group consisting of nitrogen, oxygen, and sulfur, and (C) at least one amine selected from the group consisting of (C1) a polymeric polyamine, and (C2) an amine containing not more than one amino group and at least three alkoxy- or hydroxy-substituted C2 to C12 alkyl groups R21, wherein at least one of the groups R21 is different to the other groups R21, and (C3) an amine containing not more than one amino group and at least two alkoxy- or hydroxy-substituted C2 to C12 alkyl groups R22, wherein at least one of the groups R22 bears the alkoxy or hydroxy substituent at a secondary or tertiary carbon atom and wherein at least one of the groups R22 is different to the other group(s) R22, and (C4) an amine containing at least one saturated or unsaturated C8 to C40 alkyl group R23, and (C5) a saturated or unsaturated heterocyclic amine which contains at least one oxygen atom as ring atom and which does not contain a further alkoxy group.