You can kill nutgrass in your lawn or garden through the use of chemicals, but there are several other ways to control it if you prefer to stay organic. Also called nutsedge, it isn't, in fact ...
so it may take a few weeks to kill it off entirely. It is also one of the most "gentle-to-turf" pesticides for nutsedge control, so your turf grass should be fine; however, do use caution.