You can certainly try. Amounts of less than a quarter inch depth won't deter any sprouts. I'm not sure what impact greater amounts will have on the runners...probably not much as peat moss (and even compost) are comparatively light and friable as opposed to a soil.

I'm gonna give it a try! I've been working on increasing the OM in my sandy soil (central Florida) the peat moss won't have an adverse effect on that will it?

Several years ago there was some experimenting going on with the use of baking soda as a solution to crabgrass in St Augustine. It was quite a big discussion on another lawn forum. Here's the video the guy made.

CAUTION: THIS ONLY WORKS WITH SALT TOLERANT GRASSES LIKE ST AUGUSTINE. It does not work with bermuda.

The trick is to get the baking soda to stick to the crabgrass blades. You do that by wetting the blades with water. The trick to that is crabgrass blades are hydrophobic and will shed water. The trick to that is to moisten the crabgrass blades with soapy water or with a touch of molasses in it. So you moisten the blades with soapy water, dust the baking soda on (watch the video), and sit back. The crabgrass will turn black quickly and die. The St Aug might suffer a little but it comes right back.

The St Augustine might fill in during the summer heat but it fills much faster when temps are in the 70s.

Thanks dchall! Most of my crabgrass was killed by the baking soda method prior to me pulling it out. and every time I'm out there battling that stuff I am always saying "as God as my witness I will from now on put down a pre-emergent"

Speaking of pre-emergent, when are you suppose to apply it? Do folks in Florida also do a fall application??

Heres is a pic of my little test plot. You can see where the baking soda has starting working around the perimeter. (I also put down a layer of cracked corn under the peat moss) I guess I'll just keep working out from here until I have it beat or it beats me. Unfortunately, this area is mostly crabgrass and VERY little St.augustine. I will be ordering more floratam plugs very soon!

Why is the grass thin in that spot? That's the issue. Are you mowing at the highest position on the mower? Does it get full sun? Deep and infrequent watering? Is that a sprinkler head and is that a sidewalk? Does the sprinkler water the area within a few inches between the head and the sidewalk? Or is it usually dry there?

I'm not a fan at all of sprinklers that only throw water away from the sprinkler. I use turbo type oscillator sprinklers because they put the most consistent pattern of water out.

This is my first year actually "caring for" (or about my lawn) it's thin there because for years (since 2006) it was mostly weeds. I started with only a small patch of st. Augustine under tree on the side of the house (thin area is by front door and full sun and my walkway) and I've been working to get it to spread (by following all of your advice on your 500+ posts lol and occasionally adding plugs or sprigs). And when I occasionally use my sprinklers they do wet the area around them as well but it takes 6hrs to lay down 1"