I finally broke down and sprayed the weeds in a section of my yard with MSMA after all of the other "crabgrass killers" have failed. How long should I wait to see if the MSMA works before I resort to watering my whole damn yard with hundreds of gallons of freaking roundup?

It may take a couple of times to where it is finally gone. When I've used it in the past, with 36 hours everything started to yellow. The Bermuda looks like it won't come back but 10 days later it almost back to the original green color. I would not water the grass for 24 hours after use just to be safe.

I've used Image before in a more concentrated fashion and used a dropper to individally drop down the leaves of the nutgrass. You might try that with the crabgrass or dallisgrass.

If I recall, I had to wait about a week to see results beyond my bermuda getting burned.

I had pretty good experience with MSMA 3-4 years ago working on some stubborn Dallisgrass in my bermuda. Bermuda definitely did take a hit (yellowed) but it recovered after about 2 weeks. First dose killed off about half of the patches of Dallisgrass after about a week. Second dose (two weeks later) took out about half again (so 75% total in two doses). The rest I pulled by hand (PITA). I used a hose end sprayer which the directions said not to do (I didn't have a regular sprayer at the time) so that may have had something to do with the effectiveness.

I'm at the point now where I just hand-pull what is creeping over from the neighbor's yard every few weeks. I've thought about getting some more MSMA to 'help' my neighbor out but I've got a 2 year old now and MSMA is some pretty nasty stuff.

Hopefully the MSMA works and I'll use it on the side of the house and out front. I've also got a 2 1/2 year old and don't feel comfortable using that stuff in the backyard where he plays. I'll guess back there I'll just go balls to the wall and kill everything with roundup. Sucks.

MSMA takes multiple apps to remove soft crab and dallisgrass. Like one of the posters said if you miss the 7 day interval you will be back to square one. There are better products on the golf course such as drive or dimension to take out crab. I don't know if the ai is available to the public. On Dallisgrass I found spot spraying glyphosate (round up) to be the most effective control. However it is time consuming and can make your lawn appear as if it has lepracy.