evidence: Corn gluten, the by-product of corn processing, contains proteins that inhibit root growth during seed germination for a number of small-seeded annual and perennial weeds that frequent our lawns, including crabgrass and pigweed. Not only does this product offer a natural herbicidal alternative to toxic "weed and feed" lawn products, but it, also, contains a significant amount of nitrogen that our full-grown turf grass loves. [...] Note that corn gluten will, also, suppress the germination of turf grass seeds, so either plant these seeds in locations away from corn gluten application or wait four to six weeks after for its herbicidal effects to wear off. You can likely find corn gluten products in the "weed n’ feed" section of your local garden center or online. Of course, you can always hire a lawn care company from our list of natural lawn care providers and ask them about their corn gluten services. For more resources, visit the Iowa State Corn Gluten Meal Research page.