Nice stuff. Probably can make this at home...
Turf: Corn Gluten Meal:
"Corn gluten meal is a natural product that can safely inhibit germination of grass and weed seeds.
Photo of Dr. Nick ChristiansIn 1985, Dr. Nick Christians, of Iowa State University (ISU), accidentally discovered that corn gluten had preemergence herbicide activity. The control plot of a turf fungal study showed thin seeded grass stands when pure corn gluten was used. Further study by Dr. Christians and his graduate students lead to 4 patents on corn gluten and its active components over the last 15 years. Currently over 20 companies are licensed by ISU to sell corn gluten as a natural herbicide (US Patent 5,030,268; Re 34,594).
Corn gluten is a by-product of wet milling process to make cornstarch. It is an animal feed for cattle, poultry, other livestock, fish and some dog foods. It also contains naturally occurring substances, which inhibit the growth of seed's tiny feeder roots by causing a break down in the cell wall. The seedlings struggle to get enough moisture, which causes them to die before they ever have a change to take hold. When used as directed, corn gluten acts as a preemergent natural herbicide that will not harm beneficial insects, soil organisms, pond or stream life. It is also safe around pets and children."
Since corn gluten kills only the roots of sprouting seeds, it can be used around transplants and established vegetables, flowers, fruit, shrubs and lawns. It can be used even up to the day of harvest. Once vegetable or flower seedlings have true leaves, it is then safe to apply corn gluten.
Corn gluten has another benefit. It is 10% nitrogen by weight in a slow release form. As a 10-0-0 fertilizer it can inhibit weed germination and feed your lawn and garden nitrogen. (Additional supplements of phosphorous and potassium may be needed, based on a soil test.)