Since herbicides can remain in the soil and make it unable to sustain plant life for months, many gardeners turn to natural weed-killing techniques. One such method calls for boiling water, vinegar, salt, or a combination of two or more of these ingredients.
At boiling temperatures, water will burn the leaves and roots of the weed. Without leaves and roots, the plant cannot absorb sunlight or collect nutrients from the soil.
Mix in vinegar
Vinegar has the power to kill weeds on its own, but mixing equal parts boiling water and vinegar is more effective. The acid in the vinegar and the heat from the water combine to provide an excellent weed killer.
Add salt for sidewalks or driveways
A solution of 1 cup salt, 1 cup vinegar and 1 cup boiling water will kill any weeds. Salt, however, can stay in soil for years and make it difficult or impossible for new plants to grow where it was used. Only add salt to the mixture if the weeds are in sidewalks or driveways.
Apply the solution
After making the solution, immediately pour it over weeds. The weeds should begin to die in about two days. The solution, with or without salt, can kill any plant it comes into contact with, so be careful to limit its use to unwanted weeds.