Natural methods of killing unwanted grass and invasive weeds are better for environmental, health safety and economic reasons as opposed to chemical methods. These methods use products easily found in most homes, such as boiling water, vinegar and newspapers. They are safe for the soil because they do not disrupt microbial activity, safe for children and pets because they lack harmful chemicals, and cost a fraction of the price of chemical weed or grass killers.
The most inexpensive--albeit laborious way--of killing weeds and unwanted grass is to pull them out by hand. This method is effective because it kills and removes the entire unwanted plant, along with its roots. Use this method only if there are a few weed plants or tiny patches of unwanted grass in the area. Loosen the area around the weed with a hand shovel and pull it along its roots. Discard of weeds and grass appropriately to prevent them from spreading by seeds.
Use household white vinegar to kill grass and weeds naturally. This vinegar contains acetic acid that burns unwanted and invasive pests, killing them along with their roots. For immediate results, purchase vinegar that contains 7 to 9 percent or more acetic acid. In addition, select a hot, summers day so the sun acts as a catalyst, speeding the killing process. Spray vinegar directly over individual plants or pour over areas with large infestations. This natural way of killing unwanted pests is safe because the vinegar does not leave any residue.
Pour boiling water directly over weeds and unwanted grass for an inexpensive and natural way to kill them. This method is most suited for small areas such as gaps between pathways or driveways. Pour water directly over the weeds to burn and dry them. Rake the dead weeds or grass to collect them and discard appropriately. Wear closed-toe shoes and long pants to prevent burning yourself when pouring the water.
Newspapers or Plastic
Smother unwanted grass or weeds. Mow the grass as short as possible, and spread 10 sheets of newspapers or a thick sheet of black plastic over the spot. Spread an even layer of mulch or place bricks at the corners to hold the material down and compress the grass. Covered weeds or grass die in a few weeks because they fail to receive necessary elements like water, sunlight and air. The plastic also traps and retains heat, causing weeds or grass to cook and die sooner.