A coated seed product comprises a coating 2 that contains one or more evaporite minerals 3 adhered to the exterior of a plant seed 1. Typically, the evaporite mineral(s) comprise polyhalite, which may be present in the coating in an amount of more than 50 wt.%. The evaporite mineral(s) may be a powder with an average grain size of less than 500 microns. Preferably, the coating has an average thickness of 0.1-1.0 mm and a mass of 1-20g per kilogram of seed. The coating may also contain a binder matrix 4 so that the evaporite mineral(s) may adhere to the seed. The seed may be a crop seed, such as beet, lettuce, oil seed rape, pea, rice, or wheat. A method of forming the coated seed product is also disclosed, which comprises forming a slurry of an evaporite material and a binder, coating seeds with the slurry, and drying the coated seeds.
