OSU research found corn gluten meal not effective in a study as a pre-emergent herbicide in shrub beds and on lawns. Using Cornmeal Gluten In The Garden Cornmeal is the latest natural weed killer that has been making the rounds on social media. Is it effective? Learn more.
Corn gluten meal did not prevent weeds from germinating in OSU study
CORVALLIS, Ore. – Corn gluten meal is a natural substitute for a synthetic “pre-emergence” herbicide and has been advertised as a more environmentally friendly way to control weeds.
A pre-emergent herbicide is one that kills seedlings as they germinate. Pre-emergent herbicides generally have to be applied and watered in before weed seeds germinate. Other herbicides, such as glyphosate (e.g. Round Up) kill plants after they have emerged.
A by-product of commercial corn milling, corn gluten meal contains protein from the corn. It poses no health risk to people or animals when used as an herbicide. With 60 percent protein it is used as feed for livestock, fish and dogs. It contains 10 percent nitrogen, by weight, so it acts as a fertilizer as well.
The use of corn gluten meal as an herbicide was discovered by accident during turfgrass disease research at Iowa State University. Researchers noticed that it prevented grass seeds from sprouting. Further research at Iowa State showed that it also effectively prevents other seeds from sprouting, including seeds from many weeds such as crabgrass, chickweed, and even dandelions. Components in corn gluten meal called dipeptides are apparently responsible for herbicidal activity.
Researchers at Oregon State University were not able to duplicate research results reported by Iowa State researchers, said OSU turf grass specialist Tom Cook. A former graduate student, Chris Hilgert completed his masters thesis by investigating corn gluten meal use as a pre-emergent herbicide in shrub beds and on lawns.
In their trials with corn gluten meal, Hilgert and Cook found the following:
Corn gluten meal did not control any weeds in any trials under any circumstances over a two-year period. They found no evidence of pre- or post-emergence weed control in any of their trials. Because it contains 10 percent nitrogen, corn gluten meal proved to be a very effective fertilizer, causing lush, dense growth of turfgrass and of weeds in shrub beds.
James Altland, nursery crops specialist at OSU’s North Willamette Research and Extension Center in Aurora, spoke to his observations when corn gluten was used in plant nurseries as a pre-emergent herbicide.
“I’ve seen nursery situations where the applied product caused a bad odor, as do some herbicides, and attracted rodents,” said Altland. “In nursery situations where the goal is complete weed suppression, my overall impression is that it doesn’t work that well.”
“My overall impression has been that in turfgrass it provides a lot of nitrogen,” added Altland. “Thicker, denser turf from high nitrogen rates will reduce weed numbers alone, without the help of herbicides.
“Applying 20 pounds per 1,000 square feet of corn gluten meal would be equivalent to two pounds of nitrogen per 1,000 square feet. That’s a lot of nitrogen! Applying that much nitrogen is not good for the environment. It doesn’t matter if it’s a ‘natural’ fertilizer or not. That nitrogen will ultimately be converted to nitrates, which potentially could leach into groundwater.”
It is not clear why the commercial version of corn gluten meal used in OSU trials was not effective, said Cook. One possibility is that the product as formulated for sale has a short shelf life and loses potency during manufacture, shipping and storage. Further research needs to be done to test this hypothesis, he said.
If you want to discourage weeds from germinating and growing in your garden beds over the winter, try adding mulch to soil surfaces. Use a minimum of three to six inches of composted material. Tuck mulch up to the shoulders of your perennials, but don’t cover the growing crown until freezing cold weather sets in. If you cover plant crowns too soon, they may begin to grow under the mulch and could be killed when temperatures dip.
Shredded bark, leaves, mint hay, wood chips, or yard waste all offer benefits. Large chunky material such as fresh clean wood chips and bark nuggets work best for weed control, as they are low in available nutrients so won’t fertilize germinating weeds.
Avoid mulching with hay or with ryegrass straw. Their seeds will sprout to create an unnecessary headache for you in the spring. And don’t use grass clippings from a lawn treated with a weed-and-feed preparation. The herbicide in the clippings can damage your shrubs.
A low-nutrient mulch such as well-rotted sawdust will benefit shrubs such as roses, azaleas, rhododendrons and hydrangeas. Lilies, dahlias and spring bulbs will do better with this type of mulching also. But be aware that composted sawdust or other fine organic material may contribute to weed growth.
Caneberries benefit from higher-nutrient mulches such as composted manure. Dormant vegetable beds can use a six-inch blanket of manure and leaves. Rhubarb and asparagus beds do best covered with a mix of well-composted straw and manure.
Over the winter, the composted material will mix with the soil, so a second application of mulch in March or April will keep your garden soil in better condition.
Does Cornmeal Stop Weed Seeds From Germinating
Using Cornmeal Gluten In The Garden
Is this something you have tried? We would love to hear your successes and failure along with other suggestions for organic weed and pest control, so we can share the knowledge. Corn gluten meal (CGM), is the by-product of corn wet milling. It is mainly used to feed cattle, fish, dogs, and poultry and as a food source in some less developed areas of the world. Accidental research has found that Gluten meal is a natural substitute for chemical pre-emergent herbicides, which means it can stops weeds from germinating. There appears to be lots of evidence that shows through using this cornmeal, results in a fantastic weed killer or weed preventer. Showing that it is a great way to eradicate weeds without the threat of toxic chemicals something that we are all for here at Friendly Organics. If you have pets or small children or prefer the more natural route, gluten meal is a much safer option.
As I mentioned the weed killing attributes were discovered by accident through research carried out by Iowa State University, they were actually looking into disease research but observed that cornmeal gluten acts as an herbicide as it kept grass and other seeds, such as crabgrass, dandelions and chickweed, from sprouting.
However, it is important to note that cornmeal gluten is only effective against seeds, not plants that are mature and is most effective with corn gluten having at least 60% proteins in it. For annual weeds that are growing, plain cornmeal products will not kill it but it will help prevent their spread via seeds.
Perennial weeds will not be damaged either as their roots survive and they return each year, as mentioned cornmeal will stop their seeds becoming further plants so reducing the weeding you have to carry out. With consistent use of gluten meal products, these weeds will gradually decline and eventually you should have a weed free garden.
The use of cornmeal gluten can be extended to the lawn element of your garden as grass is a well established plant and should not be effected.. Using gluten cornmeal in gardens is a great way to keep weed seeds from sprouting and will not damage existing plants, shrubs or trees. Be sure to follow the application instructions on the package and apply before weeds start to grow. Sometimes this can be a very tight window but is best done in early spring. Be sure to wait to apply in flower and vegetable beds where seeds are sown at least until the seeds are grown up a bit. If applied too early, it can prevent these seeds from sprouting. Using Cornmeal Gluten to Kill Ants Cornmeal gluten is also a popular method to control ants. Pouring it wherever you see ants traveling is the best option. They will pick up the gluten and take it to the nest where they will feed on it. Because the ants cannot digest this cornmeal product, they will starve to death. It may take up to a week or so before you see your ant population dwindling.
Cornmeal as Weed Killer?
The quest for the perfect weed killer has led to some interesting preparations. You’ll find natural remedies that range from using boiling water to vinegar and soap. While many of these remedies work, they tend to be difficult to implement on an entire batch of weeds. They also have only short term effects.
Cornmeal is the latest natural weed killer that has been making the rounds on social media. The prospect of being able to kill weeds with a simple sprinkle of cornmeal is exciting. Most people find cornmeal to be cheap and readily available, but the real question is does it work?
What is Cornmeal vs. Corn Gluten Meal?
The biggest mistake that most people take with this natural weed remedy is running out to buy cornmeal from the grocery store shelves. The type of cornmeal that you eat is not the same as what you need for weed killing purposes.
The cornmeal in your pantry is made from ground-up corn kernels. This is what you use as an ingredient in recipes for cornbread and other dishes.
Corn gluten meal is a byproduct that is created during the wet milling process of making cornmeal. It is not meant for humans to eat, but it is sometimes used in pets and cattle feed.
Since corn gluten meal has high levels of protein, nitrogen, and oils, it is also used for lawn fertilization and weed control purposes. It is sold in lawn and gardening stores rather than at your local grocery store.
How Do People Use Cornmeal as a Weed Killer?
Corn gluten meal is found in both pellets and powdered forms. The application process involves spreading it in a specific amount that is based upon how many square feet of ground needs to be covered.
After the meal is distributed evenly on the ground, you then need to water the lawn lightly to activate the oils. If the application does work, it is only effective for around 5 to 6 weeks. Then, the meal must be reapplied.
Does It Work on All Weeds?
This method only works on weeds that have not sprouted yet. People often use it on annual weeds such as purslane. Keep in mind that it will not work on perennial weeds that have already established a root system.
How Effective Is It?
There have been multiple studies on the use of corn gluten meal as an effective weed killer with mixed results. The primary issue with this method is the difficulty of applying it at just the right time to knock out the weed seeds.
Weeds grow throughout the year in Arizona. Even annual weeds may occasionally pop up before you expect them in the spring. Once they do, this method is not effective at all. It also requires frequent reapplications. Keeping up with this method can be frustrating for busy property owners.
What Are My Other Options for Dealing With Weed Problems?
Pre-emergent sprays work similarly to corn gluten meal by suppressing weed growth at the seed level, but it is a little different. A pre-emergent spray prevents seed germination. The seeds never develop roots or sprouts.
Even if you choose to experiment with corn gluten meal, you can still expect to need post-emergent weed spraying. This method gets rid of weeds that are already visible above the ground that the meal cannot kill.
So what’s the verdict? Corn gluten meal may help with preventing weeds from emerging from your lawn. This only works if you are diligent about following the proper application process and okay with it not always working.
There are also more effective methods for getting rid of those unsightly plants. Proper weed control involves a careful plan that addresses the types of weeds that appear in your lawn at every stage of growth.