Corn gluten meal is a gardening additive that is often used to prevent weeds. Care and proper application must be followed for it to be effective. In this tip, we’ll discuss what it is, how to use it, and common problems to avoid.
Corn gluten meal (also called CGM) is a byproduct of the corn processing industry that is often used as animal feed. Contrary to its name, there are no gluten proteins in CGM, but other corn proteins are present.
Corn gluten meal is used primarily in two different ways: 1) as a natural nitrogen fertilizer in lawns, and 2) as a suppressant of weed seeds.
CGM as a fertilizer has a NPK rating of 10-0-0, and provides an organic source of nitrogen as it breaks down. It makes for a great substitute for other chemical and non-organic nitrogen feeding products. CGM is typically applied at the rate of 10-20 pounds (4.5-9.0 kg) per 1000 sq ft (93sq m).
CGM is best applied in the spring and ideally when there is little to no rain predicted in the next couple of days. Water it in and then allow it to dry out. Weed seeds will try to germinate and then die off. Wait at least 6 weeks if you are trying to resow your lawn.
As a weed suppressant, corn gluten meal works by using its proteins to inhibit root formation on newly germinated seeds. Be sure to use CGM labeled as a pre-emergent herbicide as this kind of CGM has a higher protein content than CGM labeled as animal feed.
Be sure to follow the instructions, because if you don’t apply enough, you may end up feeding the weeds you were trying to suppress. CGM dos not change the soil pH or harm other grasses or existing plants (unless you apply a very large quantity of 80+ pounds per 1000 sq ft.
Corn gluten meal can be purchased at some garden centers and online.
Cover Image by Kjeannette, used under its Creative Commons license.