Using Corn Meal To Fight Plant Fungus

David Trammel's picture

I'm always looking for organic solutions to plant problems.

One of the most effective organic gardening tools is also one of the most controversial. Cornmeal is a powerful tool in battling fungal diseases on plants. (Use Brave to open)

Toxic fungicides such as Daconil and Bayleton or heavy metal products like copper sulfate are unnecessary. They kill beneficials as well as pathogens. Cornmeal doesn't work by killing, but by stimulating beneficial microorganisms. The Texas A&M AgriLife Research & Extension Center in Stephenville made the discovery and passed it along. Joe McFarland's staff noticed less disease on experimental peanuts when those crops followed corn in the crop rotation.

In that A&M research lab, grocery-store cornmeal was used. McFarland, after some prodding, told me the best results came from the Aunt Jemima brand. That didn't mean much to me until a Denton cornmeal company I helped with a horticultural product informed me that Aunt Jemima had more bran and germ particles than other products. That's what gave me the idea to use whole ground cornmeal in the garden. Cornmeal works by providing and stimulating a beneficial fungus called trichoderma. All cornmeal will work, but whole ground works best because the bran and germ haven't been removed. Much of the cornmeal at grocery stores is just the starchy inside of the corn kernel and not as effective for disease control.

Whole ground cornmeal should be used in bed preparation at 20 to 30 pounds per 1,000 square feet as a deterrent to soil-borne plant diseases. It can be used as the primary bed prep material or mixed with any of the other organic amendments. It also works around existing plants as a disease fighter, mild organic fertilizer and soil builder. Cornmeal tea can also be used for disease control. Soak 1 cup of whole ground cornmeal in 5 gallons of water for an hour, strain out the solids, and spray plants or drench on the soil around plants.

Corn gluten meal (as opposed to cornmeal) is a powerful natural "weed and feed" fertilizer and is available in powdered and granular forms. Granular is less effective, but much less messy to use. Broadcast either at 20 pounds per 1,000 square feet before weed seeds germinate in early spring and fall, or anytime you have bare soil in new beds. It prevents weeds and is an excellent organic fertilizer with an analysis of almost 9-1-1. For best results, it should be watered in after application and then go through a short drying period.

The author's website looks interesting too:

ClareBroommaker's picture

I used to have a zoysia grass lawn which grew very thick, and I only mowed every three to six weeks. That set up conditions where the lawn got an orange fungus. I had read many times of corn meal for lawn fungi control, so I tried it. Yep, it worked.

I wonder if it could help my grapes, or, say, my delicata squash whose leaves have powdery mildew. (Well, definitely too late for the squash now.)

Corn gluten meal has seen some use in my garden, too, but it was part of a mix of organic sources.