This is interesting. Apparently the OP likes the mix of bermuda and clover. And as TW pointed out, you likely would not have any clover if you had been fertilizing along the way. The next irony is that the reason you have crabgrass is the same reason you have clover. You have stopped fertilizing and the bermuda has thinned out allowing other plants to move in.

Well, you guys have convinced me. I have some crabgrass that is hit and miss in small spots around the yard but I also have some pretty good sized concentrations. Even the smaller spots with just one or two plants, the plants themselves are mature, large and spread out so that it would be fairly easy to spray just that plant and not get too much else around it. Also, the RoundUp I had for another area where I didn't want anything else growing back for a while was the RoundUp Extended Control. Regular RoundUp says you can replant after 3 days. So, I think I'm going to try and hit the worst of the infestation with RoundUp, then I'll go over the whole yard with a light spray of Tenacity for the Yellow Nutsedge. When the crabgrass starts to knock back and die off, I'll rent a dethatcher and go over the yard with that, then rent an aerator, then a power seeder and reseed and fertilize. Oh, and unless we have an unseasonably cold fall or a really fast-coming winter, we can stay in at least the mid-40s at night and mid-60s to mid-70s all the way until Thanksgiving around here. It's really hit or miss and, my luck, we'll have a really cold fall, but I'm really not too worried about sowing grass in mid to late September. I've looked at some of the information from the local county extension agents and they say that as long as the seed is in the ground by the end of September in our area, the grass should have time to be well rooted before winter hits. Sometimes it will still be good when seeding as late as mid-October but, with the way the weather is around here anything past the end of September and I'd really be pushing my luck. Soooo, that gives me a month to kill the worst of the crabgrass, dethatch, aerate, power seed and fertilize. Oh, I need to find the time to close down and winterize my pool too. It looks like September is going to be a really busy month! I may have to cancel my vacation days before Thanksgiving and take a few Fridays off instead to extend a few weekends and get everything in. Thanks for the advice guys. - Byron

Kill it now. While unattractive in the extreme, you'll limit the seed it drops. Then, remove the worst visual offenders that really stick up while you casually remove the rest if you have the time and if you feel like it--no pressure and no rush. And no worries that they're seeding out all over your lawn for next year, waiting to cause the same problem. Or worse. Next year, use a pre-emergent. It should help to limit the sprout of crabgrass, at least to some extent. If you can--it's getting tight--and if you have the inclination, reseed or move bits of existing misplaced sod from gardens and landscaping into areas where the CG is growing. Water for several weeks to establish. Feed well to encourage spread and, over time, they'll make a dense lawn that won't allow CG. You know the drill. I just don't get the stuff except in the gardens and pots. "Look good. Make people jealous." -- Kevin, Diamond City barber, Fallout 4

We run into this problem all the time when trying to restore and maintain prairie plantings. It's not just the issue of killing the grass that is there (which you have to kill ALL the roots to accomplish) it's also the problem of the seedbed, which is full of dormant seeds, which any type of tilling can bring up. This is why folks like fire, it is hot enough to kill the seedbed. That's why you would have the soil removal suggestion, to take the seeds with it. Annual weeds are easily killed by fire but I don't know about crabgrass. I suspect it is killed but still has some fight left in it for coming back to some degree. Are you planning on replacing it with grass? If so, short of burning, there are three approaches, all with pros and cons. 1. Before the crabgrass sets seed, treat the area with a strong (40% solution) grass or brush killer. I think what they sell is either glyphosate or 2-4-D. Both of these compounds, while toxic, will break down in a short period of time to non-toxic constituents. Wear protective clothing, a face mask and goggles and keep everyone including pets out of there for at least a few days. That's all that's required but I would wait two weeks before I went romping in the area. Then, when the weed killer has broken down, you can reseed. You will still have to spot treat crabgrass weeds for years to come, but it will begin to get a handle on it and that method doesn't disturb the seedbed. 2. Kill the grass with either plastic or weed killer, then when it has broken down, remove the top layer and replace with soil. I'd then sod it, because that has soil too. But you could also seed. Then spot treat weeds for all eternity. 3. Kill the grass some way, then heavily mulch and plant the grass over the mulch. You will still have weeds popping up but you will have avoided disturbing the seedbed. If it were me, I'd kill the grass and then sod.