It don't think its been widely available
for many years. I think what your reading
is trying to say is that CGM progessively reduces
weed populations from year to year because
it inhibits germination not that it takes
years and years to build up efficacy.

That is what I meant. I am just wondering if anyone has used it over the course of a few years and if they did indeed notice the weed population diminish.

I don't doubt that the corn meal gluten worked in the Iowa State tests. I just wonder how well it works out there in the real world. It has been around long enough for people to have used it enough to know. If corn gluten meal works as advertised, and if it is true that you can't burn out your lawn by applying too much organic fertilizer, I am curious why people don't lay down corn gluten a few times a year in between their applications of their preferred fertilizers.

On a related note....Two of my neighbors use an organic company. Both of their lawns are thicker and greener than the average lawn. The only weed that I notice is clover. Other than that, they look great.....

Having moved into a new house in the fall, I am in the process of doing a mixed traditional/organic program, slowly weening myself off the chemicals. The lawn was too far gone to go completely organic at first, at least too far gone considering my timeline for having it restored (I am patient, but not that patient). I love the idea of going organic, but I don't love the multi-year time period it takes to nurse a really poor lawn back to health without the services of the occassional weed treatment. Right now I am using organic fertilizer, picking most of the weeds, and spot spraying (Ortho) the problem spots. My neighbors all think I am nuts, as I am always out there picking weeds. I am hoping that a fall overseeding will thicken the lawn enough so that I don't have to use the chemicals at all next year.

I'm of the opinion that CGM works only works "so-so" on crabgrass and just fertilizes broad leaf weeds. It's powers as a pre-emergent organic herbicide are just hyperbole.

It's also an expensive way to try to control crabgrass. I have seen no testimonials here on GW of success stories using CGM for weed control. It's often reccommended...but almost no one has posted a report on it's effectiveness over several growing seasons. It's also not readily available in the retail marketplace...which says to me it does not work.

I think pulling weeds and spot spraying with WBG or vinegar along with good organic cultural practices will work better than counting on CGM to do the job.

Some times if the weeds are bad enough you have to use a little chemical to clear the lawn of undesirable plant life...then begin to cultivate your organic lawn from the clean slate.

Iowa......That is my fear. There is no shortage of people on the web telling you to use corn meal gluten as a preemergent, but few people telling of their success with it.

I have been using CGM on my St. Augustine for 10 years and I have no annual weeds or crabgrass. You need to understand the difference between an annual weed and a perennial weed such as dollar weed and wild strawberry. CGM has an element that prevents seedlings from absorbing water therefore starving them. Perennial weeds grow from runners and stolens and do not require seeds to spread themselves. Since CGM is 60% protien, that translates to 9% nitrogen, which is an excellent fertilizer for lawns and perennial weeds.

Corn gluten meal is the byproduct of the wet milling of corn to produce oil and syrup. This byproduct has been used as cattle feed for decades which is why I purchase it at feed stores.

I had success far beyond my expectations. After several years of drought most of my lawn had died off and the back half of my yard was entirely pigweed, which seeds like crazy no matter how short you mow it. Well, as soon as watering restrictions lifted I overseeded the area and got a little new grass. In early and late spring I hit the area heavily with CGM. I was merely hoping for some control but to my surprise no pigweed came up that year. Three years later I still use the CGM and pull maybe 10 pigweed plants a year, despite the fact that the grass back there is still thin.

I apply twice every spring and put down plenty of it.

You need to understand that CGM doesn't know the difference between a weed and a grass seed and effects both equally.

Rutgers....

I should've been clearer. It works great.
I can't speak for other people but one of
the reasons I don't use it more than once
or twice a year is that re-seeding is a
major part of my weed control, pull a weed
drop a seed, so I don't want a pre-m on
the ground. As for availability its all
over the place around here. Garden centers
obviously would carry it but so do a lot
of the big box stores too.

Interestingly, I use no pre-emergent at all and have no weed problems (the gardens being another story, but the lawn is clean). I did have a Poa trivialis issue, but that was in my seed.

The neighbors have massive issues. Really, feeding organically just doesn't give the weeds room to grow. The grass strangles, overshadows, outcompetes, and otherwise beats up the weeds. My dandelion count this year was six...and all at the borders and edges where grass gives way to garden.

"Really, feeding organically just doesn't give the weeds room to grow."

I've experienced the same thing. I sometimes wonder if CGM's weed prevention capabilites come more from thickening the lawn than from preventing successful germination of weed seeds. This theory would explain why the number of weeds decrease each year through repeated applications of CGM during the spring and fall.

-Deerslayer

I sometimes wonder if CGM's weed prevention capabilites come more from thickening the lawn than from preventing successful germination of weed seeds

Me, too. There's certainly enough nitrogen in it to boost the lawn into high gear at forsythia-blooming-time. Right when the weeds want to sprout.

I'm sure it helps, but I do think it's not the whole story. It's an easy test--plant seed starters with weed seeds and treat half of them with CGM.

Another issue, the preemergent value of CGM can be effected by a heavy rain shortly after application, however, this does not effect its fertilizer capability. My lawn is St.Augustine and it is very thick. The only real problem I have had is with wild strawberrries spread by birds. I spot treat these problems with 15% vinegar. Again, no preemergent, organic or chemical, will eliminate perennial weeds.

"It's an easy test--plant seed starters with weed seeds and treat half of them with CGM."

...then treat the other half with SBM or some other high N organic fertilizer. Make sure that both plots get the same amount of organic N per sq ft. Include a control plot that has the same density of weed seeds but doesn't receive any fertilizer because all good experiments have a control. Repeat the test for several years.

If at the end of the test the CGM plot has fewer weeds than the control and SBM plots, CGM probably has some pre-emergent properties. If the CGM plot has a lower weed count than the control plot but the same as the SBM plot, organic fertilizer is probably responsible for crowding out the weeds.

Are there any Ag students out there looking for a project? 8^)

-Deerslayer

I think I will start a variation on that experiment this weekend. Here is what I will do:
1) I will plant grass seeds in two different pots.
2) I will treat one with corn gluten meal.
3) I will water each daily for a few weeks.
4) I will report back here on the difference between the two bowls.

Although I am not experimenting with weeds, the effect should be the same on the grass seed. In other words, if the corn gluten meal stops the grass from successfully growing in the one pot, we at least know that there is some validity to the claims. If there is no discernible difference, then I guess it is back to the drawing board.

I think I will start a variation on that experiment this weekend.

I'd be curious to see the results! I wonder whether the daily watering isn't going to zap the pre-emergent away quickly, but I guess we'll find out.

I'd like to see the results, also.

-Deerslayer

So I came across this thread and was wondering the results of the experiment.

kathyga........I've written about it a few times here. Basically, the grass - and a couple weeds - in the corn gluten meal containers grew like crazy, telling me that it is an awesome fertilizer and not so great preemergent. I didn't get any crabgrass in that container, but I recall getting a really weird weed that I had never seen before and have never seen since. The most striking thing was the difference between the corn gluten meal and non corn gluten meal containers. When I dumped out the corn gluten meal container, the roots were REALLY deep and thick, causing the whole thing to come out in one giant clump, which was pretty interesting since I didn't spread too many seeds in there originally. The one with no fertilizer was pretty sparse in terms of root action.

New experiment for you...

Alfalfa pellets
Soybean meal
CGM

should be interesting to see if the others will produce massive root growth like CGM...

I'll give it a shot this summer. I will definitely do alfalfa and soybean, but I am not sure I want to blow another $50 just to get the corn gluten meal for the experiment. Since my next application is going to be the Scotts Organic Choice Lawn Food, maybe I will make that my third application. If anyone wants to send me a small baggy of corn gluten meal, let me know and I will give you a mailing address. Just remember, my experiments are highly unscientific. In other words, a "real" scientist would laugh at them. However, I would be happy to conduct the experiment and keep you guys updated with photos every step of the way.

bump

I realize this is an old thread, but FWIW here's my experience with corn gluten meal. In 2001, I looked at the bag of Turfbuilder and my baby rolling around on the grass and said No. Nothing was applied to the lawn that year which let the weeds build up. So the next year, corn gluten meal it was. I was too late for crabgrass prevention, but the dandelions were in full bloom. Can't recall if I applied it once or twice that year, but the rebloom of dandelions was much less than I expected. I used it from 2002-2010 once or twice a year and was very happy with the results. The grass was thick and healthy and weeds were minimal. Dandelions were the main issue I had with that lawn and the control was good. Only downside really was it was more expensive.

I have not read the research (thanks for the link!). How much time would I need to allow after fertilizing with CGM and then overseeding in fall?

You'll have to check the link for a time frame, but corn gluten inhibits seed germination. When I decided to go with the corn gluten, I knew I was giving up the idea of overseeding in the near future. You would probably do better to do a conventional weed control/fertilizer if needed, followed by seeding and wait to start corn gluten in the spring. If you do a better job than I did, you'll actually get it on in time to prevent crabgrass:)

I have not seen anything that addresses cookingofjoy's question, however, if you spread Corn Gluten Meal in the spring you will be able to overseed, successfully, in the fall. They do say the CGM needs to be spread about 6 weeks before the unwanted plant seeds will be germinating.

Thanks! In just general searching the 6 week window has been mentioned. Another source said 60 days before trying to seed. I think I'll end up waiting for the season change!