According to the USDA, vinegar can be used as an organic way to kill weeds in gardens and yards. However, the acid concentration of vinegar has a direct correlation to how effective it is as a weed killer. Household white vinegar, which is the type that is most widely available, has a 5 percent acid concentration. It is able to kill very young weeds (those that are less than 2 weeks old) successfully when sprayed directly on them.
Fill a clean, dry spray bottle with white vinegar. Add a squirt of mild dish soap to the vinegar and swirl gently to combine. The dish soap will not kill the weeds, but it will help the vinegar stick to the weeds.
Spray the vinegar solution directly onto young weeds. Make sure to aim a direct stream onto the weeds. The vinegar can also kill grass and other young, delicate sprouts that may be growing in the same area as the weeds. However, white vinegar is too weak to infiltrate and kill roots, so it will not damage other plants if it doesn't come in direct contact with them.
Repeat the process daily to kill existing young weeds and keep new sprouts at bay.
Pull more mature weeds by hands, digging up their root systems with a spade. Keep an eye out for young weeds that may grow in those spots; kill them immediately with the vinegar solution.