History

• A serendipitous discovery unveiled corn meal gluten's herbicidal qualities. Dr. Nick Christensen of Iowa State University used corn gluten meal as a medium for a fungal disease study on grass. The grasses treated with either the fungus-inoculated or fresh corn gluten meal didn't grow, and the research team realized corn gluten meal had potential as a natural herbicide.
  
  

Effectiveness

• The University of Illinois Extension states that, during the first year, corn gluten meal reduces weed growth by 50 to 60 percent. Only effective before crabgrass and other weeds sprout, corn gluten meal requires repeated annual or biannual applications for four to five years before it fully controls weeds. Corn gluten meal is also a plentiful source of nitrogen, encouraging thick, weed-preventing lawn growth.
  
  

Problems

• Corn gluten meal stops the germinating crabgrass seed's root growth. Without a healthy root, the seedling soon dies from dehydration. Unexpected rainfall can keep the crabgrass alive, however, and corn gluten meal's high nitrogen content gives existing weeds a boost. Also, because corn gluten meal is a byproduct of corn, it may rot or attract mice and other pests.