The invention relates to a method for producing a protective layer on a surface of a plant, to a protective layer for a surface of a plant, to a plant coated with said protective layer, to a composition for carrying out the method and for producing the protective layer, and to uses of said composition. According to the invention, a method is proposed, wherein at least one sol gel having nano-scale particles is formed by the hydrolysis of at least one precursor in water and at least one nano-scale layer of the sol gel is applied onto the surface of the plant. The protective layer according to the invention comprises a nano-scale SiO2 layer, and the composition according to the invention comprises at least one SiO2-producing substance.