It was quite by accident Iowa State University found that corn gluten can be used as a natural herbicide. It is completely organic, and is non-toxic to animals, making it an environmental option in weed control for the lawn or garden.
It is the non-chemical version of weed and feed because it also contains nitrogen which feeds the lawn. It only kills the weeds when they are sprouting and leaves all the other plants unharmed.
Corn gluten is the starchy part of the corn kernel and is what is left over after it has been processed in the making of corn syrup and regular corn starch. It is often used in the making of pet and livestock feeds because of its high protein content.
Corn gluten is a pre-emergent herbicide, and how it works is that it prevents sprouting seeds from developing a root system. The seeds germinate and form a shoot but does not form a root and so it will die. All existing and established plants are left unharmed if the product is used following the instructions on the container.
If it is used at a very high rate it could inhibit the plant's roots on mature plants. If you already have existing weeds in the lawn such as dandelions, etc they will have to be removed using another method. Once all the existing weeds have been removed the corn gluten will prevent any more weed seeds from developing.
Because corn gluten only works at the time of germination, timing is important. You want to apply it early in the season just before or as the weeds are germinating, because as soon as the seed develops a root it is too late. Apply it to the area in early spring when the forsythia comes into bloom or two weeks before the early flowering bulbs such as crocus show their colour. It will be effective for five or six weeks if put on properly. After applying it to the lawn it has to be watered in within two days of application but do not overwater as too much moisture will reduce the effectiveness of the product as it leaches out the protein. Then, a short dry period of four to five days would help because if it is kept too moist the moisture could help the plant recover and form roots later.
If you are putting in a new lawn or reseeding over an existing lawn do not use corn gluten until after the first mow or two to three weeks after reseeding, because it will prevent the grass seed from forming roots as well. It is non selective and prevents all germinating seeds from developing roots, so never apply it on a windy day as you do not want the product to go where it is not supposed to be. It can also be used in the vegetable/flower garden but you need to be careful if you are planting seeds. I would only use it in the area of the garden where there are already existing plants or where transplants will be planted.
Corn gluten is an environmental way of controlling weeds such as crabgrass, creeping bent grass, dandelions, foxtail etc. in the lawn as well as naturally feeding and thickening the turf grass.
A product that corn gluten is used in is Turf Maize Bioweed 'n' Feed.
