Gallery is my best friend on lawns and ornamental beds with broadleaf weed problems. Specifically, spurge and oxalis. I do not get a lot of dandelions here, but those other two weeds are horrific. The cheaper and more commonly used preemergents do not work very well, even if it is on the label. I do well to make up a tank mix containing say Dimension or Barricade plus Gallery.
Gallery is a "Must" for centipede and St. Augustine turf. It has a gentle effect on root pruning forming on stolons. These are sent out above ground and form penetrate into the soil. I like to use a tank mix with Dimension as Greendoctor said in the spring when the stolon growth is benign and straight Gallery thru the active growing season. Gallery mixes well with your other soluble materials.
So I'm guessing that gallery as a pre on warm season lawns is best? I'm I correct that you guys are mixing it with diminsion or prodiamine early on? I do split apps of pre. Do this also with gallery or just one app? I've always used prodiamine only and most lawns are doing good. I've been wondering about switching to something else for warm season that won't affect turf spreading.
What's the price of gallery? Are you useing the normal rate of prodiamine and gallery in your mix?
Prodiamine has the strongest effect for root pruning. It lies on the surface longer than most pre thus attacking hair roots of invading weed seed. Actually it fry the hair root and keeps the seed from attaching to the soil--it does the same for the newly forming hair root of the stolon.
If my memory serves me correctly Gallery is the best for broadleaves but will not stop grassy weeds like crab and goose, so you have to mix it if you want to stop the grassy weeds. I have never used it but have been told by almost everyone that it is a night and day difference for broadleaves though.
A good reason to use Gallery as the basis for broadleaf weed control in warm season turf is herbicide tolerance. Many warm season grasses do not tolerate Three Way, triclopyr or fluroxypyr as well as a cool seaon lawn. With a long growing season, it is also very easy to go over maximum usage rates of the post emergent herbicides that a warm season grass will tolerate. I rather prevent spurge in a warm season lawn rather than attempt to kill it emerged. Especially if I have already subjected the lawn to a postemergent program already that year.