After cutting a lawn, it is not uncommon to see thick, grass-like, coarse yellow stalks popping up. This is called sedge, and the most common lawn sedge is nut grass. Although nut grass is easily confused with regular grass varieties, nut grasses in the sedge family have a triangular stem as opposed to regular grass' circular stem, and also has thicker leaves growing in sets of three. Control nut grass with hand-weeding or herbicide.
Remove nut grass by hand by digging down slightly and removing the root ball and pulling up with a gloved hand. Top growth will reappear in a few days if the complete root system is not removed.
Place a weed cloth over a fallow area that is not planted or tilled but still has nut grass for two to four months. Place two 10- to 12-inch spikes fitted with a flat washer to secure the weed mat into the soil. Allow enough slack for air to circulate, says the University of Hawaii at Manoa. Nut grass seed will germinate and choke itself off from receiving light after several weeks.
Apply glyphosate herbicide to nut grass after is has grown for two to three months to maturity. Apply the herbicide according to the packaging instructions and allow one to two weeks before planting any new plants in the area to allow the herbicide to wear off.