A herbicidal composition comprising an aqueous suspension of microcapsules is provided. The microcapsules have a capsule wall of a porous condensate polymer, wherein the microcapsules contain a solution of clomazone in a solvent system comprising one or more non-edible oils. A method for preparing the composition comprises providing a water immiscible phase comprising clomazone, an isocyanate and optionally an ACD cross-linker, dissolved in a solvent system comprising a non-edible oil； providing an aqueous phase comprising one or more surfactants； combining the water immiscible phase and the aqueous phase to form a dispersion of the water immiscible phase in the aqueous phase； thereby forming microcapsules of polyurea containing droplets of the water immiscible phase； and curing the microcapsules.
