Grass can spread a number of ways, through seeds, or through runners. Because grass can spread below the ground, it can creep into flower beds under barriers. Although a number of commercial weed killers will work on grass, these may not be the best method for killing weeds in children's play areas, vegetable gardens or herb patches. Instead, use a nonchemical home remedy to kill grass.
Weed block is one method that landscapers use beneath mulch to prevent the spread of grass into flower beds. Create your own landscape barrier using home refuse such as cardboard boxes or newspaper. Newspaper or cardboard can also be used under mulch, or placed directly on the surface of soil to kill grass by blocking sunlight from the grass plants. Barrier methods of killing grass must be left on the surface of soil up to 6 months to completely kill the grass beneath the cardboard or newspaper.
Solarization is literally a method of baking plants and soil to kill not only the grass, but the seed resting in the soil. Once solarization is complete, the soil must be improved if you want to grow any plants in the soil. This is because the process will kill not only weeds and weed seeds, but also any beneficial microbes in the soil. To solarize the soil, cover the area you want to solarize with clear plastic. The grass beneath the soil should be damp in order to build a hot, humid environment under the plastic. Once the sun rises, temperatures beneath the plastic can rise up to 140 degrees F. This will cook the grass as well as anything in the soil.
Contact Weed Killers
A number of grass killers for your lawn can be found in your pantry or medicine cabinet. Vinegar contains mild amounts of acetic acid, which will kill weeds by poisoning them on contact. Place vinegar in a spray bottle and spray it directly on grass, or saturate a cloth and swipe the individual blades to remove them. Isopropyl alcohol will also kill grass on contact by drying out the blades. Neither vinegar nor alcohol will kill the grass rhizomes or stolons, so this is just a temporary solution.
Pour boiling water directly onto weeds to cook them down to their roots. This is a good method for killing weeds growing through patios or cracks in the sidewalk, because there are no desirable plants nearby to kill in the process. Boiling may not be the best solution for vegetable gardens, because the boiling water will cook anything that it comes in contact with.
No matter how frequently you remove grass stems, as long as you leave the roots behind, the grass may return. One very labor-intensive, yet very successful, means of removing weeds is to dig them out of the soil. This process is known as grubbing. Loosen the soil around grass weeds by inserting a shovel or spade into the ground. Then pull up the roots of the grass by hand or with a soil cultivator or rake. You must get all the roots from the soil in order to prevent the grass from returning.