Vinegar is effective for controlling nutgrass. Nutgrass is a weed native to Eurasia. It is evasive and can be hard to get under control. It is known to ruin lawns in addition to choking flowers and vegetables.
Pour white vinegar into a spray bottle and spray it directly on the nutgrass. Keep it away from plants or grass you don't want killed. Reapply on re-emergent growth as needed.
With an invasive grass such as nutgrass, vinegar may not be enough by itself. According to Howard Garrett a two pronged approach is best. Let the problem area dry out, and then dig out the plants and spot treat with the vinegar spray.
Horticultural molasses is an effective, nonchemical solution for nutgrass. Combine 1/4 to 1/2 cup of liquid horticultural molasses per gallon of water and drench the problem areas. Sprinkling 3 to 5 lbs. of dry molasses per 100 square-feet of nutgrass also works.