You can apply corn meal gluten at any time. The warmer, the better, as it requires the microbes in the soil to break it down. I don't know anything about zone 9, though, so I can't say what will germinate.

I am not sold on corn meal gluten working as anything more than a good fertilizer. However, some - and by "some" I think I can safely say about 10% of the people who have tried it - swear by it. BUT, I would say there are two reasons to put it down:
1) Research on it has suggested that it needs to be put down over several years to get the optimal benefits.
2) It is a very good fertilizer. I grew grass in a planters this year as an experiment and applied corn meal gluten to some of the planters. Wherever the corn meal gluten was applied, the grass grew like CRAZY - deep, deep, deep roots.

Here is a link to the Iowa State University Corn Gluten Meal Research page describing the research behind using CGM as a preemergent. According to the research done by Iowa State Univiversity, it works by inhibiting the root formation of germinating plants.

Much of what I've read about the CGM research indicates that the amount required to make it work properly is pretty high. I suspect that those who are seeing only fertilizer benefits are not applying it thickly enough. I've never used it as either a fertilizer or a pre emergent, but the research done by ISU is pretty conclusive.

bpgreen......I agree with your assessment. BUT, if it requires a dose that will break your bank AND it takes several years to really see a difference, I am wondering if it is worth it. I am going to keep applying it, but my skepticism is pretty high.

I noticed something else while rereading the research.

Here is a quote from the first of the links on the page above:
"After germination, a short drying period is needed to kill the plants that have germinated but have not formed a root. Timing is critical. If it is too wet during germination, the plants will recover and form a root."

This alone could account for some of the failures people are experiencing. If the dry period isn't there, then there is no pre-emergent effect. It even mentions the fact that it makes a great fertilizer for germinated weeds.

The author of that paper recommends that it is usually applied at a rate of 20 lbs/1000 sq ft, but also suggests testing it at rates as high as 80 lbs/1000 sq ft.

I agree that if it's used correctly as a pre-emergent, it's very expensive. But if you want to have a fully organic lawn, the only choice for a pre-emergent is CGM.

I think the best defense against weeds is proper cultural practices (deep infrequent watering, proper fertilizing, proper mowing height, etc) and I think that if you can get your lawn healthy enough, a pre-emergent isn't necessary.

If you're going to use CGM as a pre-emergent, you need to use it correctly if you want it to work. That means that you need to time the application correctly, you need to use enough for it to be effective, and you need to have the drying period after germination.

I've never used a pre-emergent, whether chemical or organic. It's usually a disadvantage to try to have a lawn in the desert, but unless I water improperly, I don't have to worry much about weeds or fungus.

Everything I know about CGM as a pre-emergent is what I know from reading the research on it rather than personal experience. But the research is pretty clear. If it's applied at the proper rates at the proper time and there is a drying period, then it stops weeds from establishing.

If you're not applying enough CGM, or you're applying it at the wrong time, or you're not giving it the post germination drying time, then the only benefit you're getting from it is the fertilizer benefit. In that case, there are much less expensive fertilizers you could use.

I suspect that the reason it fails for most people is the post germination drying time, since so few of us have any control over how much water our lawns get and when they get that water.

That's why I don't use CGM. Can't trust mother nature to do her job properly... Otherwise it's nothing more than very expensive fertilizer.

Raymondo17,let me see if I can add a little sanity to this discussion. First, you need to understand the difference between annual weeds, those propagated by seeds, and perennial weeds, such as dollar weed that spread by runners and sometimes stolens. CGM will control annual weeds but does an excellent job of fertilizing prennial weeds. So, you need to figure out what you are trying to control. CGM is 60% protien which translates to 9% nitrogen. If you need to control annual weeds such as dandelions and crabgrass, timely applications at a rate of 20# per 1,000 sq. ft. of lawn can be effective. I am in zone 8 and I make my fall application right now and my spring application around the first of March. I have very thick St. Augustine which often simply crowds out weeds.

Texasredhead,

Are you sure it is CGM's pre em or is it the fertilizer itself which is very potent doing the job crowding weeds out?

I have st augustine and I have never used CGM on mine and I have very little weed problems. I just apply soybean meal and mow high.... That does the job pretty well for a lot less money...

I have mostly gravel in my backyard, and want to use CGM to prevent weeds from growing. I won't use other chemicals because of my dog, and can not keep pulling the massive weeds, especially after our rainy seasons. Right now, I have no skin left on my fingers from pulling weeds all weekend since I have to dig into the rocks with my fingers to grab the weeds by their roots. (I just gave up and sprayed most of them with vinegar/water/detergent and pray we don't get rain to wash that mix into areas that I have things planted...)

Has anyone had success with CGM in gravel?

Aerating soil is only needed if the soil is very compacted and lacks sufficient organic matter in the soil. If it is needed then it could be done in the fall and compost, or other organic matter could then be spread which will, eventually, loosen the soil so more mechanical aeration is unnecessary.
The first thing to do to assure a lush, green lawn next year is get a good, reliable soil test so you know what, if anything, needs to be done to feed the soil that will feed the grass plants. If your soil pH is out of whack nothing you feed your lawn will help maintain lush, green growth. There is some Nitrogen in Corn Gluten Meal and one of the side affects of using it is to put some N in your lawn, but applying this pretty expensive material in the fall is probably not a good thing since most all "weeds" will be going dormant for the winter and few "weed" seeds will be germinating during the winter, even in California.

If seeds sprout, and then having a drying period, the sprouts will die. Again, timing is everything.
I've used CGM, and I'm not convinced of it benifits per cost. It's an excellent fertiliser, and does a great job of crowding out the weeds.

I'm using it for the first time next May to control crab crass. I bought a bag of Bradfield Organics Luscious Corn Gluten 9-0-0 Organic Fertilizer, it cost no more than my Ringer fertilizer and here in NY crab grass is a annual. It only grows during the warm months starting in June so that will give it a month start to begin building up in the soil. It's said it last 60 days in the soil.

I must report that after using W.O.W. corn gluten last fall and spring, I still have an awful lot of crab grass showing up in my relatively new lawn. And I mean, a lot. :(

I've done some searching, but haven't found a clear answer...so here it goes:

Would using a chemical pre-M such as dimension or AMAZE one time in the Spring (when the Forsythia blooms) and perhaps one time in the Fall be so terrible with an otherwise completely organic lawn care regimen...just to be clear, I wouldn't be using ANY chemical fertilizers, strictly a chemical pre-emergent used once during Spring/Fall.

Reason why I'm asking is b/c from all the reading I've been doing, it seems that CGM may not be completely reliable as a pre-M given that it requires up to 80#/1k and perhaps a dry period after application...

Thanks

Corn Gluten Meal is effective as a pre emergent for about 6 weeks, providing the soil is dry after application. After that is becomes a fertilizer. Since, generally, fall is cooler and moister than late spring, applying CGM in the fall, for weed suppression, would not work as well as it would in late spring, and it would be a very expensive lawn food.

"Since, generally, fall is cooler and moister than late spring"...

I would think with all of the rain in Spring, it would be more difficult to keep the ground dry then.

Many people think of rain when they think of spring but when the plant seeds start to germinate and grow the rains are pretty much over with.

I think it really depends on your location -- for example, we (Vancouver and suburbs) can get a lot of rain pretty much into May at times (as do some areas of coastal Washington State), so if we were to put down CGM at the time the forsythia is blooming, there's a pretty solid chance that there will be no drying out period for several weeks afterwards.

So, if that is the case where you live in an area that is prone to 'no drying period" after the appropriate time to put down CGM, would using a synthetic pre-M (and only pre-M, no fert) such as dimension or amaze be acceptable or would it completely destroy the biology of the organically treated soil?

I'm not sure how a synthetic pre-M would affect the biology of the soil -- I'll leave that to the experts on here?? I'd be interested in knowing this too.

However, in my community, many stores (even some Home Depots) have stopped stocking anything that has non-organic herbicides or pesticides, since our city council is close to banning such chemicals for cosmetic use (and some other communities already have). Thus, I don't even know if I can buy synthetic pre-M near me.

I've basically resigned myself to handpicking my weeds, and hoping that my cultural practices will help. Although the part about infrequent watering, when you live in a very rainy area, is hard to control, and the weeds seem to love it.

bumping in the hope that dchall reads this :-)

I've had a rough summer. Thanks for bumping it.

Would using a chemical pre-M such as dimension or AMAZE one time in the Spring (when the Forsythia blooms) and perhaps one time in the Fall be so terrible with an otherwise completely organic lawn care regimen...just to be clear, I wouldn't be using ANY chemical fertilizers, strictly a chemical pre-emergent used once during Spring/Fall.

Reason why I'm asking is b/c from all the reading I've been doing, it seems that CGM may not be completely reliable as a pre-M given that it requires up to 80#/1k and perhaps a dry period after application...

First of all there are no organic police to bang on your door, and we can't come through your screen to strangle you. Do what you want. If you are looking for permission to put chemicals on your lawn, that's between you and Satan ;-)

More seriously, I've never had any luck with any kind or preemergent so I don't use them. I occasionally use CGM as a fertilizer but I don't pay any attention to blooming plants when I apply. It is my general opinion that chemical herbicides are worse for soil microbes than chemical fertilizers; however, I have not paid any special attention to preemergents to try and understand them more than superficially.