Corn Gluten Meal as weed supressant: can you over-apply this?

16 years ago

Hi, I'm new here. Not sure where to post this... it's actually probably an "organic landscaping" question, but there is no forum for that I can see. I also x-posted this in organic lawn care and organic gardening.

I decided to replace a large area of lawn around my home with landscaping. It's a sloping hill off the side of my house and was really hard to mow anyway. It's about 1,000 square feet. I planted in lots of native spring ephemerals and native bushes, surrounded by hardwood mulch.

The trouble is, I have silver maple trees along the driveway right next to this area. They drop thousands of propellers in spring, and I found that keeping the area weed and maple seedling-free was nearly impossible by hand.

So I followed the advice posted in another thread on this site, and I went to the feed store to get Corn Gluten Meal as a pre-emergent for weeds. I got a 50 pound bag for just $22. Apparently this product is marketed as Organic Preen and under other brand labels, but it's much more expensive than buying the raw stuff from the feed store. Long story-- Iowa State University accidentally discovered CGM's weed suppressant abilities, and now they license it. Meaning they collect money from products like Organic Preen. Anyway.

So I applied CGM to the area before re-mulching with hardwood bark. I could not tell what setting to put my spreader on. Everyone says it's 20 pounds per 1,000 square feet. I ended up putting the entire 50 pound bag down on my 1,000 square foot area.

Now, the area smells. Really bad. Like something fermenting or rotting or both. Could I have done major damage? Why would it smell that bad? I've done numerous web searches and found nothing. I'm sure the smell is from the CGM. I just hope a bad smell is the only negative... could I be ruining the soil or hurting the plants with this over-application? I wish I had been more careful, but this is what happens when you are working with a product from the feed store that has no label on it to help you know how to spread it.

I guess what I'm trying to say is, please don't berate me for making a dumb mistake... that much I know. If you have helpful info on what I can do to correct any potential problems that might arise, that would be good. I'm also just really curious where the smell is coming from. Does corn ferment when there is too much of it?

Thanks for your thoughts.

Sort by:Oldest

Comments (4)

Embothrium
16 years ago
Â Corn gluten meal (CGM) is a protein-based, natural product with potential pre-emergent
herbicide activity
Â CGM has no effect on established weeds
Â CGM is not selective and can inhibit germination of desirable plant seeds as well as weeds
Â Though it may be effective in the Midwest US, CGM is not as effective in other climate zones,
such as those in the Western US
Â There are no scientific data from field trials in the Western US to support the use of CGM in
weed control
Â Other environmentally friendly weed-control treatments (such as sub-irrigation, mulch, or soil
solarization) are cheaper and often more effective than CGM

Here is a link that might be useful: The Myth of Weed-Killing Gluten
hoovb zone 9 sunset 23
16 years ago
It might be rotting. If you could cultivate it into the soil the smell might dissapate faster. It will be organic material for the soil.

Someone on another forum a couple years ago was talking about CGM for weeds, nonfat milk for mildew and eggs for rabbit repellant, and I thought, that's not gardening, that's corn bread!
Related Professionals
Ocala Landscape Architects & Landscape Designers · Baltimore Landscape Architects & Landscape Designers · Philadelphia Landscape Architects & Landscape Designers · Tyler Landscape Architects & Landscape Designers · Peoria Landscape Architects & Landscape Designers · Santa Maria Landscape Architects & Landscape Designers · Frisco Landscape Contractors · Georgetown Landscape Contractors · Farmington Landscape Contractors · Ogden Landscape Contractors · Sarasota Decks, Patios & Outdoor Enclosures · Webster Decks, Patios & Outdoor Enclosures · Albany Decks, Patios & Outdoor Enclosures · London Decks, Patios & Outdoor Enclosures · Queens Decks, Patios & Outdoor Enclosures
gardengal48 (PNW Z8/9)
16 years ago
You won't hurt the soil by over-applying :-) It is totally organic and will breakdown like any other type of organic matter and feed the soil. CGM is actually a decent organic source of nitrogen (NPK 9-0-0), so the only drawback to over-applying is that your plants may produce more lush, leafy growth, including any weeds that were not removed prior to application. What you are smelling is the natural process of the meal decomposing in somewhat anaerobic conditions because of the mulch cover - water and warmth will encourage and speed up this process but exposing the meal to air should dissipate the smell rapidly. Maybe rake off the mulch, leave the CGM exposed for a few days, then recover with the mulch.
Marie Tulin Boston burbs z 6a
16 years ago
We had the same experience. We got into the situation by leavning the cmg bag open, and it got soaked by rain over a period of days. About a week later, the smell was enough to make you hurl. And it became invested with flies. If ;you've read Patricial Cornwell, it was how I imagine the body farm would smell and look.

We dumped it as far away in the back garden as we could. When I used it correctly, it did not smell. I didn't use it long enough to see if suppressed weeds over a long period of time. A few posters on the New England Forum swear by it.

Marie