Mar 14, 2014 - 12:42 PM
The best time to treat these weeds are during the early warm growing season. Depending on where you live it may be too early to spray. Typically, the grass has 3-4 small blades and is actively growing.
Using a surfactant or a few drops of dish soap also helps to allow it to stick to the grass blades.
Nutsedge is difficult to control. I have found extremely good results on my personal yard with a product called Certainty. Image is a good product, but in extreme nutsedge or nutgrass infestations, you may need some professional quality herbicide.