When weeds sprout, use common household cleaners to save a trip to the garden center. Some of these home remedies are natural, break down quickly and pose no threat to humans or pets. Keep in mind, even seemingly harmless things, like mixing vinegar and bleach can be deadly. These two components are usually safe as stand-alone cleaners/weed treatments, but when mixed together, they form deadly chlorine gas. Before mixing items, get a professional opinion on whether or not it is safe to do so.
Use vinegar for quick results. Use household strength vinegar without diluting it. Grasses and other weeds die, usually overnight when thoroughly doused with vinegar. Soaking the plant and root zone gives the best results. Vinegar is non-selective, killing desirable plants as well.
Salt works quickly, dehydrating and killing all common weeds. Use this method dry or mix with water and spray on plants. Keep in mind that salt will not break down---it changes your soil so that your future desirable plants may not grow where the earth was salted.
Use alcohol to dehydrate plants quickly. Apply it full strength or make a strong alcohol to water solution. Apply daily until weeds begin to die off. Avoid over spraying as this solution kills garden plants as well.
Use boiling water as a spot treatment for all types of weeds. It works quickly, killing the leafy part of plants as well as their roots. Deeply rooted, long taproots may need further treatment. The good thing about boiling water is that it leaves no harmful residue or other deposits behind. This makes it safe to plant seeds and plants as soon as the soil cools.
Dish soap alone does not effectively kill weeds; it does, however, aid other treatments in that department. The degreaser in detergent-type soaps breaks down the waxy coating on plant parts---and allows weed killers to work properly. Use 1 to 2 tsp. per gallon of weed killer.