Corn meal can be used for three different purposes--fungal control, soil conditioning, or feeding your lawn. This is the same corn meal available at any grocery store, although it tends to be much less expensive at a feed store or grain mill. You can also use cracked corn, although you may notice that it attracts birds and a few corn stalks may grow. Those corn stalks will not survive mowing, or you can pull them if you like.
Corn meal will help control and cure fungi such as brown patch and dollar spot. Studies done at Texas A&M at Stephenville, TX indicate that it is not effective on rust.
For fungal control, 10 to 20 pounds per thousand square feet is sufficient. Generally, 10 pounds per thousand square feet is used to prevent fungal infections, while 20 pounds per thousand will control an infection you already have. You should see an improvement after approximately three weeks, and can reapply the corn meal as often as once a month. You can also apply it only when you see a developing fungal issue purely as a curative.
Corn meal attracts trichoderma fungus which is harmless to your lawn, giving your invading fungus less room to grow. Tricoderma also has the ability to kill other fungi, which is a major advantage when fighting a fungus problem in your lawn. However, for severe infections chemical controls may be called for, after which corn meal can be used as a control to limit future outbreaks.
For soil conditioning, anything from 10 to about 60 pounds per thousand square feet is fine. Your worms like to eat fungi and bacteria, and the corn meal will support large numbers for your worms to dine on. Additionally, bacteria and fungi themselves help condition your soil by attaching soil particles together using glomalin, increasing the soil's structure.
Amounts over 10 to 20 pounds per thousand square feet may produce odor when the corn meal decays, however many people report that even amounts much greater do not smell. That amount will vary depending on the weather--damper and warmer weather will cause some odor on lower amounts, whereas cooler and dryer weather will allow greater amounts before odors appear.
Feeding the Lawn
Corn meal is not the best grain to use to feed your lawn. Granted, organics don't feed the lawn directly, however there are higher protein (nitrogen) meals available such as soybean that don't require the amounts that corn meal does. Additionally, corn meal doesn't contain large amounts of phosphorous or potassium, making it a less effective fertilizer overall. Around sixty pounds of corn meal per thousand square feet would be required at least twice yearly to feed the lawn. By comparison, fourteen pounds per thousand square feet of soybean meal at least twice a year will feed the lawn at the same level.
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