I use all of the grass clippings, leaves, etc. that I can get my hands on. I've been known to steal the neighbors' bagged grass clippings out from under the nose of the lawn waste pickup truck driver more than once, believe me.

There are few "disadvantages" to doing this, but a couple of things to think about:

1) if the lawn was freshly treated with herbicides, don't use these on herbaceous plants -- there could be some residual contamination. Allow a couple of weeks after a lawn treatment for this to diminish. When I treat my lawn, I use the first few cuttings to mulch around large trees or paths, places where I know this won't be a problem.

2) Athough they're pretty high in nitrogen, like any organic matter, the microbes in there can temporarily suck nitrogen and some other nutrients from the soil during the decomposition process. So, be sure to add a little extra fertilizer to the garden to compensate for this.

3) As they decompose, grass clippings can develop mold which can be a problem for people with mold allergies. So, if this is you, be sure to wear a face mask (the cheap paper disposable type) if you must dig through or disrupt the mulch after its down.

4) IF the lawn is full of weeds, uncomposted clippings may contain weed seeds. You'll have to judge that one for yourself -- if you lawn was white with dandelion seed heads when you mowed, you might want to compost this batch of clippings before using.

Green clippings or dried, doesn't really matter a whole lot, either way is fine. Don't let the factors above scare you away from using a fine, free source of mulch and compost, just be aware of them.

How much should I put on? I have read that using too much can cause heat from decomposition and hurt the plants.
Would the depth change between dry and fresh grass?

Another disadvantage you might have in TX (and hopefully not in Michigan) is that some harmful insect pests can use the straw to overwinter the larvae. I am thinking particularly of harlequin bugs, but I think this could apply to other bugs. No difference if it is grass or another natural mulch though. I think it is just a disadvantage or mulch in general. I still mulch because the advantages outweigh the disadvantages, at least in our dry weather.

Since you are in Texas, it's possible you could have Bermuda grass? If so, I would STRONGLY discourage you from using it as mulch. A stolon only 3/4" long or just a couple of seeds can lead to years of heartache. Bermuda is the Terminator of the grass world.

Bermuda would be a real nightmare if somehow a stolon/runner got in there. Otherwise, heat of decomposition for any application you can do is not an issue. Go for it.

Dan

Concur with the posts above. The only disadvantage that I have is some types of dried grass mat and form an impenetable layer that water will not penetrate. Have not had a problem with fresh cut. I would strongly suggest that you incorporate the mulch into the soil at the end of the season. As cabrita stated, if you leave that mulch on over the winter, it provides habitat for a host of pests that overwinter in soil. That includes squash bugs, Harlequins, field mice, voles and the list goes on.

On the other hand, my freshly cut grass mulch never lasts more than 2 or 3 months. I only add it in May, before things start going to seed, and there is never a need to turn anything in October. Grass is also good to mix with browner stuff (straw, leaves or chips), to have a faster decomposing mulch, if desired. Say you mix it with leaves in May, spread it under the garlic, in August when you pull the garlic you can plant lettuce seedlings, they will like it.

Does anyone know how many inches thick is optimal for grass mulch?

Grass clippings are my mulch of choice....also in Michigan. I don't dry them - the grass grows so fast in May and June that any left on the lawn cannot be seen long before they dry. I plop them in the garden fresh - dandelion seed heads and all - throughout May and June. I plant close, in 3' wide beds, so by July the plants are pretty thick and the need for mulch diminishes.

I lay them on green, about 4" deep....pulled slightly away from seedlings. It dries pretty quickly.

As I mentioned, dandelion heads go right in. The mulch prevents them from germinating. The very few dandelions I get are easy to pull. My most persistent veggie garden weed is tomatoes.

Kay