Weed killers are used to alter cell structure in weeds thereby affecting their growth or ability to live. Natural weed killers are a good method to kill individual plants and spot applications in flowerbeds. Many natural methods started as home remedies to common weed problems.
Mix vinegar with 15 to 20 percent acetic acid. Put the mix into a spray bottle and spray directly onto the weeds. This makes vinegar a very strong weed killer. Look for the mixture to have an effect within 24 hours after application. Three applications are needed before the effect is long-lasting because single applications have short effective durations. Bleach is a variation of this method; apply bleach directly to the weeds, but be careful because this treatment also damages surrounding plant life if applied in a broad range.
Boiling water is one of the oldest weed killers. Heat water in a metal container to a rolling boil. Immediately pour the water over the weeds. This action burns the foliage, roots and ground while drowning the roots simultaneously. Boiling water is a fast acting home remedy, but does not last long and will need repeated applications for weeds that continue to return. After the weeds are burned, pulling them out by the roots can eliminate the chance of their return. Steam is a variation of this home remedy. Use a hot steam sprayer to apply steam directly to the foliage.
Salt is a home remedy that is very effective, but must be used carefully and in limited amounts. Salt is a fatty acid used to dissolve plant membranes. Salt also dehydrates plants quickly. Make a saline mixture in water to spray on the foliage and roots. Be careful not to apply too much, or use continuously for weed applications. Salt remains in the soil because it is not bio-degradable and remains in any runoff from rainfall. This causes excess salinity to spread and damage surrounding plant life.