How to Use Corn Gluten Meal as a Weed Killer

Are weeds a constant battle in your lawn or garden? Corn gluten meal (CGM) offers a natural way out. It's a by-product of making corn that's rich in proteins. These proteins stop weed seeds from growing roots. This has made corn gluten meal a safe choice for keeping weeds at bay for more than 30 years. So, how can you use it to enjoy a weed-free area? Let's uncover the secrets to using this organic weed killer.

What is Corn Gluten Meal and How Does it Work as a Weed Killer

Corn gluten meal comes from the corn milling process. It was first a supplement in animal feed. Now, it's used as an organic weed killer. Unlike chemical herbicides, it's a healthy choice. It has 10% nitrogen which feeds plants and helps control weeds like crabgrass.

It's important to note how it works. Corn gluten does not stop seeds from sprouting. What it does is stop the new plants from rooting. So, to work, it must be spread before the seeds sprout. Then, the area must stay dry a bit to activate the gluten.

How well corn gluten works as a weed killer varies. It's excellent against new weed sprouts, especially the ones that grow yearly. Yet, it doesn't work as well for deep-rooted weeds that come back every year. The best weed control comes from combining different methods for weed stages before and after they grow.

After applying it, corn gluten stays effective for a month and a half. The right time to use it depends on the weeds you want to stop:

  • To stop some weeds before summer, apply it in the early spring when the soil is around 50 degrees Fahrenheit.
  • To stop certain winter weeds, use it in late summer as the days get cooler.

To really beat the weeds, experts say use corn gluten meal in spring and early fall. After using it several seasons, studies show up to all weeds can be kept under control.

See also
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Types of Corn Gluten Products and Identifying the Right One

When using corn gluten to kill weeds, knowing the different types helps. Many corn products get mixed up with corn gluten meal, which fights weeds. For example, corn meal isn’t strong enough with its 8-9% protein. And corn gluten feed (CGF) isn’t the right type either, coming from the wet milling process.

Corn gluten meal is the best for weed killing, with a high protein of 60-65%. It's crucial to find a product labeled as a herbicide. This ensures it's the right type for keeping weeds away.

Let's zoom in on the types of corn gluten and what they're for:

  • Corn Gluten Meal (CGM): This has 60-65% protein. It stops seeds from growing roots. That keeps weeds from taking over your garden.
  • Corn Gluten Feed (CGF): Made from the wet milling of corn, this product is mainly animal feed. It only has about 20% protein, making it unfit for fighting weeds.
  • Corn Meal: A food-grade item for cooking and baking, it contains 8-9% protein. It's not strong enough to kill weeds, unlike corn gluten meal.

Make sure you pick the right stuff by checking the label for "corn gluten meal". Then look at the protein content. This step is key for great weed control in your yard.

How to Use Corn Gluten Meal as a Weed Killer

Corn gluten meal may help with weeds naturally. Yet, you must use it the right way to get good results. It should go on before weed seeds start growing, which happens at various times.

Applying corn gluten meal happens:

  • In late March to mid-April if you're stopping summer weeds
  • In late August for winter weeds

Corn gluten meal stops weed roots from growing. This stops weeds from taking hold. After you put it down, make sure there's no rain for 48 hours.

Put down at least 20 pounds for every 1,000 square feet. You can use up to 40 pounds for better results. Lightly water it after spreading to make it work.

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To do this right, you must apply it at the right time and amount. Plus, you need to pick days without rain. This way, corn gluten meal can keep your garden weed-free. It's a safe choice for both you and the environment.

Effectiveness of Corn Gluten Meal on Different Weed Types

Corn gluten meal fights a bunch of garden and lawn weeds. It's great on weeds that grow every year. This is because it stops them early, when they're just trying to sprout. But remember, its success can change based on the weed and how and where it's growing.

This meal does well against many weeds like crabgrass, smartweed, and dandelions. It stops the roots of baby weeds from growing. So, they can't get a good start to life. And it doesn't need to touch the whole weed to work. This is because it stops weeds when they're just starting to grow.

When it comes to yearly weeds, corn gluten meal is a star. Yet, it isn't perfect against weeds that come back every year. Since perennial weeds might grow back, it's harder to tackle them fully. But, using it can still keep the new perennial weeds in check, maybe making fewer weed babies over time.

At first, using corn gluten may seem slow to work. It might need a few tries to show full control. But keep applying it right, and it can handle up to 80% of the weed problem.

Weed Type
Effectiveness of Corn Gluten Meal
Annual Weeds (e.g., crabgrass, smartweed, lambsquarters)
High (up to 80% control)
Perennial Weeds (e.g., dandelions, redroot pigweed)
Moderate (can limit germination of new growth)
Established Weeds
Low (does not affect mature weeds)

In short, corn gluten meal is a powerful ally against many weeds. It's especially good with yearly weeds just trying to grow. But, it might not work as well on all weeds. How you use it is key to its success.

Where to Buy Corn Gluten Meal and Cost Considerations

Corn gluten meal, or CGM, comes in powder, granules, and pellets forms. You can get it from local farms, feed stores, and online shops. The protein content should be 60-65% to work well against weeds.

See also
How to Keep Deer Out of Flower Beds

CGM needs about 20 pounds for every 1,000 square feet. It can cost more than synthetic herbicides. You might need to apply it several times a season for the best results. Yet, using it more adds up to better weed control over time.

Price per Pound
Application Rate per 1,000 sq ft
Cost per Application
Corn Gluten Meal (60-65% Protein)
$2 - $5
20 lbs
$40 - $100
Soybean Meal (6-1-2 Analysis)
$0.25 - $0.50
15 lbs
$3.75 - $7.50

While CGM can be pricier, it's a natural, organic way to fight weeds. It also adds nitrogen to the soil, acting as a fertilizer. For those who care about the environment, CGM's benefits can make it a smart buy.


Corn gluten meal offers a natural choice to synthetic weed killers. It can work well as a pre-emergent tool to fight off weeds in yards and gardens. Its mode of action is to stop the roots of weed seedlings from growing. This stops them from taking hold.

The key to success with corn gluten meal is all in the timing. It must be used before the weeds start to grow. Also, it's important to get the amount you use right. Plus, you need dry weather after applying it for the best results.

Even though corn gluten meal could cost more and needs more effort, it offers lasting benefits. It keeps weeds at bay over many years if used consistently. Homeowners should weigh the advantages and disadvantages based on their needs. With the right care, this method can keep lawns and gardens healthy and free of weeds.

In the end, corn gluten meal is a solid pick for those who want to steer clear of synthetic options. Learning about its pros and cons is important. This way, gardeners can utilize it correctly and see their outdoor areas thrive without weeds.

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