Corn meal is fine on a lawn, but soybean meal available from grain mills and sometimes other places is much higher in protein and thus higher in nitrogen.

Corn Gluten meal is also fine, but it can also have pre emergent qualities that inhibit germination of seeds. Fine if you are trying to prevent early season weed seeds from sprouting, but not so good if you will over seed your lawn within a month or so of using it.

Corn meal is the whole meal, and not just the corn gluten, so it is less effective as a weed pre-emergent, but it does work as a fertilizer, and slightly as a pre-emergent. Since you HAVE the corn meal, and don't seemingly want to cook with it, then you can go ahead and spread it on the lawn. As implied above, it will inhibit seed germination for about 4 weeks, maybe more, so don't use it where you plan to sow grass seeds. It is a slow release fertilizer, so you won't see results immediately. If you want to spread it lightly on your flower beds you can, as long as you aren't expecting any flowers to come up from seeds. You can get CGM at either a feed store or garden supply place, although it might be cheaper at the feed store. It acts strongly as a pre-emergent weed killer, and then as a fertilizer later. Neither CGM or corn meal will have any root-killing effect on plants that are well established, only on newly sprouted seeds.

Sugar feeds the soil bacteria, which are what break down fertilizers, organic matter and "stuff" in the soil. So it will help give a flush of bacteria, but they won't stay in large quantities, as the population is only as large as the food supply. Sugar won't act as a weeed killer. If you have a compost pile, and you have extra sugar, you can add it to the pile, to enrich the bacterial population, and hasten the breakdown of your "raw materials", or you can scatter it with the corn meal on the lawn. If you water it in, then pets should not be attracted to it, although bees and wasps might be....

If you can't or don't want to pull the weeds, you can spray them with plain household vinegar, mixed with a little soap to make it stick better. This will kill whatever it gets on - although it works better on a sunny, warm day, over 65F. It will kill only the green parts, and is NOT a systemic, like Round Up, so the roots may survive and sprout again, and need to be re-sprayed. Just be careful, especially if it is windy, that the vinegar hits only what you want dead.

Plain corn meal is also an universal natural fungicide, as well as a great economical protein fertilizer.

I use bulk size bags of cracked corn and cheap corn based no-salt animal feed products also as a corn meal substitute for feeding my beneficial soil micoherd.

Happy Gardening!

Thanks for posting those questions, mamacat. I'd been wondering the same thing. I do have one additional question that I hope someone can answer...

If you use corn meal in the garden to inhibit weed seeds, how thickly do you need to spread it?

The application rate for corn meal as a relatively weak protein source is 10-20 pounds per 1,000 square feet. If you already have a fungal disease, you need to use it at 20 pounds per 1,000. How much is too much? With corn meal you could probably apply 40-50 pounds per 1,000 before you notice a sour smell about a week later. But once you experience that sour smell, you will NEVER use that much corn meal again. Try this: put a teaspoon of corn meal in a jar of water and set it on your counter top until it sours (about a week).

For ground grains with more protein in them (which is almost all of them), you can use them at anything under 40 pounds per 1,000 and not worry too much about the smell. Actually the smell is only a problem for people with noses. The microbes love an overdose of food.

Questions about the smell. I am new to organic and been reading as much as I can about it. I applied a 100lb bag of soy meal about 3 weeks ago and now it really smells. I probably applied too much as my lawn is not very big, ~3000 sq/ft.

Typically, how long will the smell last? Is there anything I can do to alleviate the smell...lawn lime, etc?

Thanks.

Hi Chris,
I replied to this over on the organic lawns forum. You applied way too much of the high protein soy. Cornmeal has a lot less protein and can be applied at a higher rate. It is the decomposition of the protein that seems to cause the smell. It should be gone in a week. Next time apply at 5-10 pounds per 1,000 square feet. See how it works and adjust your application rate from there.

It might not help much now but the same situation that often causes compost to smell if too much nitrogen rich materials are added without a balance of carbon to keep the ratio right is probably part of what happens when too much meal is spread. I don't know how much it would help spread out on a lawn but perhaps spreading some carbon material over the soy meal would help balance the ratio and reduce the smell. Something like sawdust, peat, finely shredded leaves, or even a thin layer of compost. You wouldn't want to spread too much and smother the grass crowns but organic matter is good for all soil.

Doesn't corm meal draw pests such as mice?

Good question Kathy. You would think it would but it does not...at least not out in the yard. In the yard it turns moldy (decomposes) almost immediately when it gets wet, so the mice never have a shot at it. However, you should not store corn meal or any other organic fertilizer in your garage over the winter. That might attract mice.

A side benefit of using corn meal is that it does attract birds for a day or two. If you get omnivorous birds (like most seem to be), they pick out the bugs from the yard.

What of sugar for the micoherd ?