If you’re spraying a clethodim-based herbicide for the first time, there are a few things to know. One, although it will kill mature grass, it seems to work best on young grass, so the best time to spray it is in the spring. Two, don’t expect the same rapid results from clethodim that you get from glyphosate. A field sprayed with Roundup usually turns yellow within a few days. In my experience, it takes a couple weeks for grass to wilt after you spray it with clethodim. Follow the label, and have confidence and patience. Three, clethodim will kill oats and wheat, so if you're one of the many plotters who oversows with those cereal grains, don't spray clethodim. Finally, while most glyphosate blends have surfactant mixed in (this helps the chemical stick to the plant), most clethodium herbicides do not, and so you’ll need to buy surfactant** separately and mix it in when you’re filling your sprayer tank. Surfactants are pretty cheap, and they’re available at about any farm supply store.