Plan the perfect garden with our interactive tool →

How to Use Rock Salt to Kill Roots or a Stump

tree stump image by Radoslav Lazarov from

Simply cutting down a tree isn’t enough to kill the roots left underground. Those roots are still alive, which virtually assures that the tree will regrow by sending new shoots out of the stump. Using salt is a cheap and effective way to kill tree roots and accelerate the rotting process of the stump. The best time of year to kill tree stumps is from late May through mid-August. This is when their growth declines as they prepare to enter winter dormancy.

Cut the tree stump down to ground level.

Drill some holes into the sides of the stump near the top of it. Make them as large as you can, and drill them at about a 45-degree downward angle pointing toward the center of the stump.

Pack the holes full of rock salt. The holes will help to circulate the salt through the stump and into the roots, hastening the killing action.

Spread a generous band of rock salt on the ground around the stump. Water it into the soil thoroughly until you don’t see any crystals remaining. Then apply another band of salt. This should prevent the stump from growing anymore and kill the roots. Don’t put salt on any vegetation that you don’t intend to kill.

Cover the stump with fertile topsoil, which contains bacteria that will help to break the stump wood down. Rotting wood in soil attracts beetles and other insects to feed, further assisting the process.

Rock Salt To Kill Roots Or A Stump

Tree stumps and roots can cause problems long after a tree has been cut down. Stump removal and stump grinding can be expensive, while burning out stumps or using harsh chemical stump removers may be dangerous or even illegal without a permit. You can use rock salt, however. Cut the stump down as close to ground level as you can. Make the hole large enough that you'll be able to pack it with salt, at least 1 inch in diameter. Pack the holes with rock salt, getting as much of the salt into them as you can. Cover the stump and the holes with soil, then cover the soil with mulch. This water helps the salt to dissolve and be absorbed by the roots and stump while also encouraging the growth of fungi and other organisms that will decompose the stump.

Garden Guides