A new slow-release fertilizer is described that is formed by applying graphene oxide (GO) as a carrier for micronutrients such as copper (Cu) and zinc (Zn), in which the micronutrients are efficiently bonded with the functional groups at the surface and sides of the GO sheets due to their affinity to the unpaired oxygen atoms in the GO. The prepared Cu-graphene oxide (Cu-GO) and Zn-graphene oxide (Zn-GO) fertilizers showed a biphasic dissolution behaviour compared to commercial zinc sulphate (ZnSO4) and copper sulphate (CuSO4) fertilizer granules, displaying both fast- and slow-release micronutrient release.