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Dallas Morning News - September 5, 2019

Disease Control with Cornmeal (and more) SHORT version


One of the most effective organic gardening tools is also one of the most controversial. Whether it’s black spot on roses, purple spots and yellow leaves on photinia and Indian hawthorn, brown patch in St. Augustine grass, early blight on tomatoes, or damping off in newly planted seedlings, cornmeal is a powerful tool. Toxic fungicides such as Daconil, 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 A&M Research Station in Stephenville, Texas made the discovery and passed it on to me. Dr. Joe McFarland's staff noticed less disease on experimental peanuts when those crops followed corn in the crop rotation. But - A&M today shrugs off questions about cornmeal and never brings it up as a recommendation for disease control. Go figure!


Most grocery store cornmeal lacks the bran and germ

Whole ground cornmeal is one of the best microbe stimulators


In that A&M research lab, grocery-store cornmeal was used. Joe, after some prodding, told me that the best results came from 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 brand and germ particles than other products.


That's what gave me the idea to use whole ground cornmeal. 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 hasn'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 20-30 lbs. per 1000 sq. ft. 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.


Corn gluten meal ungranulated is messy but effective


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.


Granulated corn gluten meal

Closer view - granulated corn gluten meal


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 lbs. per 1000 sq. ft. 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 dry period. By the way – it's time for the fall application in turf.


Cornmeal converts quickly and efficiently to sugar and the beneficial trichoderma fungus benefits from that process. That 's why I have it in my sugar amendments category, but also why you shouldn't eat too much. Very fattening stuff!




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