After cutting down a tree, the roots can make it difficult to remove the entire tree stump. Tree roots grow outward, and over time, as soil erodes, tree roots often appear on the surface. You can kill these tree roots naturally without the use of chemicals. Epsom salt, also known as magnesium sulfate, will kill the roots of a tree by absorbing moisture from the wood. By depleting the roots of the needed moisture, they will become dry, therefore killing the tree roots naturally.
Cut the tree stump down level with the ground. Remove soil as needed to expose the entire base of the tree.
Drill holes into the top of the tree stump. Make 1-inch holes in all four corners of the stump. Drill the holes to a depth of 1 foot or as deep as you can.
Fill a bucket with warm water. Pour 16 oz. of Epsom salt into the water. Stir the mixture until dissolved.
Place a funnel into one of the drilled holes. Pour one-quarter of the mixture into the hole. Repeat this process on all four holes.
Dig around the roots of the tree using a grub hoe. Expose as much of the roots as possible.
Pour the Epsom salt mixture over the exposed roots. Ensure you apply a thick layer. This will prevent the roots from absorbing nutrients and water.
Reapply the mixture each week for one month. After one month, the bark should start showing signs of dryness. Dead wood will be dark and brittle. When the wood is dead, remove the stump and dead roots. If the bark is light in color, reapply the mixture as needed.