How to Kill Nutgrass in Lawns

Apply a pre-emergent herbicide evenly over the lawn that contains dichlobenil in the early spring right before soil temperatures favor nutgrass growth. Pre-emergent herbicides are only effective against yellow nutgrass. However, pre-emergent herbicide helps prevent yellow nutgrass from popping up during the growing season. Water the lawn after applying the herbicide.

Dig up young nutgrass plants, using a hoe, when they sprout five to six leaves. When removing nutgrass' extensive root system, use a hand hoe and dig to a depth of 8 to 16 inches. Patches of nutgrass must be removed by digging up the weed.

Add dirt to the bare areas that formally grew nutgrass, so that the lawn is level. Broadcast starter fertilizer or a fertilizer that is high in phosphorous in these areas. Use a fertilizer that has an NPK, nitrogen, phosphorous, potassium, amount of 5-10-5 at a rate of 20 lbs. over the bare areas and work into the first 2 to 3 inches of soil. Seed or install turf grass in bare areas.

Spray nutgrass with a post-emergent herbicide that contains halosulfuron and MSMA, or monosodium methyl arsenate. Post-emergent herbicide is at its most effective against nutgrass that has less than five leaves. Choose a dry day to apply the herbicide.

Spot treat nutgrass growing in the lawn with a broad spectrum herbicide that contains glyphosate. Broad spectrum herbicide kills surrounding grass; therefore, gardeners must choose dry, wind-free days to apply the herbicide to nutgrass.