That is NOT crabgrass. I've no clue what it is, but it's not crabgrass, which tends to be more horizontal and rather angular looking.

It looks like something Weed-B-Gone won't touch, with or without Crabgrass Control, as it's something I occasionally pull from my gardens. :-)

Hopefully somebody can ID it and give you a good control, but at the very least I can assure you that WBG isn't going to cut it here.

Brown grass--This can be caused by dry weather conditions, disease, insects, or half a dozen other things. Are there areas where it's worse than others? If so, is there anything distinctive about that area? In my case, I've a little browning on my southwestern face because it tilts into the sun.

Search crabgrass seedling. Large crabgrass new leaves are rolled in the bud and the entire leaf blade is pretty hairy. Smooth crabgrass new leaves are rolled in the bud but the leaf blade is less hairy. This picture is a crabgrass plant and the picture you posted from a couple of weeks ago was much more mature crabgrass. The Weed-b-gon version of quinclorc requires you to make two apps to kill crabgrass. I have never used the Weed-b-gone version, I use Drive a much high percentage of of quinclorc. The Weed-b-gon label says it kills crabgrass with two apps until the crabgrass reaches 3 to 4 inches aka mature crabgrass. The Drive version will kill most mature crabgrass. This is the problem with winter or summer annual weeds by the time most home owners notice them they are mature and impossible or almost impossible to kill. So your options are buy Drive or use the Weed-b-gon on the smaller plants and pull the larger crabgrass plants. Looks like you have a tall fescue/kentucky bluegrass lawn? I think the brown grass you see in there is the kentucky bluegrass going dormant, it will bounce back when conditions are right.

So one vote for crabgrass, and one vote NOT crabgrass. Guess I'll just keep pulling it by hand for now.

Most of the browning is in my back yard, which was existing lawn when we purchased the house last year, so I'm not sure what the exact makeup is. I guess it would make sense that it's KBG because the front yard, which was started from scratch last September, is all tall fescue and pretty green throughout (aside from a few spots where trees were removed which I'll repair in September).

While I'm on the subject of varieties of grass, there is one spot in my back yard, I'd estimate about 8' x 8' area, that is definitely different than the rest of the lawn. It bothers me that it's not consistent. Can anybody tell from the picture what this is, and what is the recommendation to transition it to tall fescue?

Does this new grass spread over and under ground? It looks like one plant of bermuda with no stolons or rhizomes. Where do you live?

You think you're giving it enough water. How often do you water and for how long each time? And how do you adjust when it rains?

This may be a stupid question, but how I determine if it is spreading underground? I pulled another pinch and this time I got what I believe it a rhizome...you be the judge.

I'm on the Jersey shore, zone 7a.

As far as watering goes, I've been trying to just keep an eye on it and set it to run a cycle when I think it's drying up. Last Mon-Wed we received about 5-6" of rain and temperatures have been very moderate since then, so I haven't run my sprinklers since then, but planning a cycle tomorrow. Much of the lawn really greened up (this could also be from the Milorganite I applied July 7), but some brown grass still exists. My 8-zone system takes about 3 hours to complete. The zones with rotary heads (where the brown grass is) run 30 minutes each. I was running the sprinklers 2-3 times a week when we were getting little rain and temps were in the mid to upper 80s, but I cut back since then because I was informed (by you, actually) that it was probably too frequent and causing my crabgrass issues (which unfortunately is still thriving..assuming that's what it is). I have yet to do the tuna can test...maybe I'll try tomorrow.

And here's a photo of my back yard so you can see the brown areas I'm talking about.

The camera didn't really pick it up but if you look very closely in the upper-middle of the picture you can see the patch of this other unknown grass. It's a slightly different green, and much different texture.

That's a better picture. It looks like bermuda or zoysia. Does it get a seed head that looks like this? If you can get a picture of the seed head that will help to identify it.

If all the lawn still looks nice and fresh and green, I would not water tomorrow. Wait until the grass looks wilted. Don't go by the condition of the surface of the soil. It should dry out completely long before the grass needs water again.

Crabgrass will die by itself. Some imposter weeds will not and need to be pulled out or treated.

I don't think I've ever let it get long enough to see any seed heads, so I can't tell you what it looks like. Whether it's zoysia or bermuda, does that impact the best way to get rid of it? My goal is to switch it to tall fescue this fall. I don't think I want to spray it and risk killing good grass. Should I just scalp it with a weedwacker then rough up the surface before seeding with TF?

I'll hold off on the watering...I was out pulling more crabgrass tonight and the grass is not wilting. I also pulled some plugs of soil and it's still moist.

Regarding the brown spots...I stuck a screwdriver in them and the soil was just as moist as the green areas, but there seemed to be some considerable stones an inch or two under the surface. Could it be that there are so many stones the roots can't penetrate deep enough?

Looks very much like a creeping bent. It generally will crash in the heat of the summer, but it's an extremely persistent perennial and will lie low till rainfall and cooler temps break its summer dormancy.. Those grey-green patches of fine textured dense turf are way too familiar! If you're not commonly seeing this same grass in older home lawns in your area, it then most likely was 'delivered' in some grass seed that was applied at some time. Most often these unimproved common bents tag along with harvested seed and find there way into lesser quality seed. I'd suggest investigating bentgrass controls. Tenacity is more selective, but slower. Glyphosate will get it, but rarely the first time. Try to keep it in check as the patches will only grow larger and it will gradually dominate all other cool season grasses, ie KB, PR, TF, etc.

Bentgrass makes a lot more sense. There are very few bentgrass issues on this forum, so you sort of forget about it. The only two discussions I can remember were from people using it as their primary turfgrass. Woodycrest was a golf course manager just north of Lake Erie. He used creeping bent with a mix of Dutch white clover on his organic pitch and putt courses.