Corn gluten meal is a product of the wet milling process. It is a pre-emergent herbicide which inhibits root formation during germination. Data suggest it has at least some activity on an even wider variety of plants. It is safe to use on established turf. DO NOT use corn gluten meal in an area in which you are trying to establish turfgrass.
Studies suggest that control is improved in successive years and as use rates increase.
It is sold for the homeowner market in retail stores as Concern-Weed Prevention Plus. Until recently it was only offered in powder form. Now a granular form is available which can be more easily be applied with Vikon spreaders, rotary and drop spreaders. The nitrogen is in a slow release form so there is little to no potential for foliar burn. Portions of at least two proteins in the corn gluten meal, called peptides, are the active ingredients in corn gluten meal.