Method for producing seed preparation by iron coating

The present invention provides: a method for producing a seed preparation by iron coating, whereby it becomes possible to rapidly elute a herbicidal compound in a herbicidal composition outside the system of seeds without causing chemical damage to crops themselves, particularly paddy-field rice plant, and it also becomes possible to control grown weeds particularly in a paddy field at a practical level; and others. In the process for producing a seed preparation by iron coating, seeds are treated with a properly formulated herbicidal composition before the termination of the oxidation reaction of an iron powder.