Aug 20, 2018· To kill a tree stump, start by drilling holes across the top of the stump that are at least 8 inches deep. Then, fill up the holes with Epsom salts or rock salts and seal them shut with melted candle wax. Once you've filled and sealed all of the holes, cover the stump with a plastic tarp or trash bag and wait at least 6 weeks for the stump to die.