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 Recent social media posts suggest using household cornmeal to control garden weeds. Looks simple enough, but does it work? Cornmeal is simply ground corn that we use in cooking. It is an essential ingredient in cornbread and corn muffins. Although it might add some nutrients when sprinkled on the garden, it likely does not have any effect on weeds.
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.
Organic weed control: Corn meal gluten
Recent social media posts suggest using household cornmeal to control garden weeds. Looks simple enough, but does it work?
Cornmeal is simply ground corn that we use in cooking. It is an essential ingredient in cornbread and corn muffins. Although it might add some nutrients when sprinkled on the garden, it likely does not have any effect on weeds.
Corn gluten meal (CGM), on the other hand, is an industrial by-product of grain wet-milling. It is used as feed material for cattle, poultry, fish, and dogs. Kelly Allsup, horticulture educator with University of Illinois Extension explains more about using corn gluten for organic weed control in lawns and gardens.
In 1988, Iowa State scientist Nick Christians discovered that CGM is a growth regulator by accident. During an experiment, he studied the effects of five corn derivatives, among them corn gluten meal, on the survival of potted creeping bentgrass. In a surprise result, CMG had a profound effect on the growth and development of the grass, suppressing its growth by 80 percent at the lowest dose applied and 100 percent at twice the dose.
Eager to find out more about the weed-suppressing ability of corn meal gluten, Christians tested it as a herbicide against grasses such as crabgrass. Field tests in the late 1980s that applied 20 pounds of CMG per 1,000 square feet in the spring with another application in the later summer to early fall gave good control. This procedure controlled 60 percent of weeds in the first year, 80 percent in the second, and 90 percent in the third.
He also showed that CMG is an effective pre-emergent herbicide, suppressing other grasses and broadleaf weeds, such as annual bluegrass, black medic, buckhorn plantain, lambsquarters, dandelion, foxtail, purslane, and redroot pigweed. Growers can use it for controlling weeds in strawberries, radishes, onions, garlic, saffron, herbs, and grapes. As a bonus, CMG is an excellent fertilizer.
Allsup notes that success of CMG depends on some environmental factors. “Application timing is critical because it must be done before weed seeds germinate. The highest efficiency is observed during the third and fourth year of treatment. Weed plants that have already germinated will not be controlled,” she explained.
Equally important, Allsup noted that CMG must contain 60 percent protein. There are brands on the market that do not contain enough protein to be effective. Allsup also advises against watering the lawn after application, or applying CMG soon after a rainfall, because wetness will reduce its effectiveness.
The take-home message is that a homeowner who would like to try organic weed control with corn meal gluten should acquire the appropriate product, apply it at the right time before weeds germinate, and apply from year to year. Check local garden centers and nurseries to see if the product is available.