CGM (Corn Gluten Meal) is all natural. I put it down like fertilizer; but you need to put it down in Jan/Feb for spring weeds and Oct/Nov for winter weeds.
the natural gardener's site says to put it down in Feb and also has this-
Now is the beginning of the window to put down CGM for control of weed seeds that germinate in the spring. The use of CGM came from Iowa State University researcher Nick Christians by accident when he was trying to use CGM to grow a pathogen found on golf course turf. The experiment did not work but he found that the CGM could inhibit root growth. It will work best on seeds that germinate on or near the surface of the soil. Weeds controlled by CGM include crabgrass, dandelions, pigweed, purslane and others. Corn gluten will prevent successful germination of seeds, but it will not kill weeds that are already established. It is applied at the rate of 20# per 1000 square feet. Corn Gluten has a 9-0-0 nutrient analysis so it will act as an early non-toxic "Weed & Feed". Come April or May, if your grass is not as green and healthy as you would like, feed it again with Lady Bug 8-2-4. Remember, CGM prevents seeds from germinating so it needs at least 60 days to break down before you seed the area with grass, vegetable, flower, or any other seed. CGM should also be applied in September/October for fall germinating weed seeds.
i have bermuda as well. it has worked well for me. the only time i have not used it was my 1st year in the house and that was the worst spring weeds i have ever had.
