Use household products to kill unwanted grass instead of purchasing commercial grass killers. Not only are store-bought ones harmful for the environment, they are dangerous if you have children or pets, and cost more as well. Among various household products, homeowners commonly use newspapers, vinegar and water to kill invasive or unwanted grass.
Spread heavy dark-colored plastic over an area to prevent sunlight and air from reaching the roots of unwanted plants and eventually killing them. Plastic absorbs moisture and traps it, choking plant roots to kill them completely. Although it is easily available in most home improvement stores and garden centers, use black garbage bags as a cheaper alternative.
Mow the unwanted grass very short and spread a layer of plastic over it to cover it completely. Weigh the edges of the plastic down with rocks or landscaping blocks to prevent it from shifting. The grass will choke and die in a few weeks. The biggest advantage this method offers is it serves as a natural weed barrier, even after the grass is dead. Do not remove the plastic, but cut holes in it where you want to plant shrubs or flowers and spread a layer of mulch over it when you finish planting.
Use newspapers for a cheap but effective way to kill unwanted grass. The biggest advantage newspapers offer is that they eventually decompose in the soil, without harming it. Mow your unwanted grass short and wet it slightly. Spread overlapping black-and-white newspapers over the site until they form stacks of eight to 10 sheets. Moisten them again to prevent them from blowing away and weigh them down with an even layer of mulch. The grass will smolder and die in a couple of weeks due to no contact with air and water. You do not have to remove the newspapers as they will eventually biodegrade in the soil.
Another popular home remedy for killing unwanted grass is a commonly used household item---white vinegar. It contains acetic acid that targets the cell membranes, thus drying up and killing the unwanted plant. Use this home remedy in the hot summer months when it is most effective. Pour directly or spray vinegar over unwanted grass, covering it completely. The grass eventually dries up and dies. Reapply after a few days to kill stubborn grasses.
Pour boiling hot water over small areas of unwanted grass to kill it immediately. This method is effective for areas such as cracks in driveways or paths, or between bricks where a few unwanted grass plants grow.