Vinegar when sprayed on plants, drain moisture from leaves and the plant dies. It is an organic and inexpensive way to kill weeds. But beware; it kills every plant that comes in touch with it. Take one gallon white vinegar. You can use the vinegar that we use in kitchen; its concentration is 5%. However a 10% or 20% solution works faster. Mix one cup salt in it if you have rock salt, add it. You can use table salt, too. Add one tablespoon of lemon juice in it. If you are using 10% or 20% solution you can skip using lemon juice. Now add two tablespoon of dish soap and stir it well. Keep reading the tutorial in the source.