How to Use Rock Salt to Kill Roots or a Stump

Killing a tree stump allows it to decay naturally over time.

Killing a tree stump allows it to decay naturally over time.

Tree stumps and roots can cause problems long after a tree has been cut down. A stump or root system can go on living for years, resisting decay and spreading new roots or growing additional shoots that eventually grow into new tree trunks. 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. This removes excess material from the stump that someone could potentially trip over and helps to ensure that the salt will make it to the roots and not just be distributed through the trunk stump.


Drill into the side of the stump at a downward angle as close to the top of the stump as you can get. Make the hole large enough that you'll be able to pack it with salt, at least 1 inch in diameter. Drill additional holes every few inches around the stump; the larger the stump is, the more holes it should have.


Pack the holes with rock salt, getting as much of the salt into them as you can. If you are not concerned about grass or other plants that surround the stump, you can also place a line of additional rock salt on the ground close to the stump.


Cover the stump and the holes with soil, then cover the soil with mulch. Pour water over the soil and mulch to help dissolve the salt and to pack the soil in around it.


Water the stump every 2 to 3 days for several weeks, or more often during dry conditions, saturating the 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.


Check the stump and roots periodically, adding more soil and water if needed to encourage decomposition. If you notice new growth appearing from the roots or around the stump, cut off the new growth and repeat the salting process to deplete nutrients from the wood and kill the stump.

Things You Will Need

  • Saw
  • Power drill
  • Rock salt
  • Soil
  • Mulch


  • Adding fertilizer that is high in nitrogen to the area around the stump will further encourage the growth of fungi to speed up the decomposition of the stump and roots.
  • Some trees such as ash trees, hawthorns and Norway maples tolerate salt more than other varieties and may not die off quickly when applying salt to their stumps.


  • As roots break down, small sinkholes and other soft spots can develop around the tree stump you salted. Fill in these holes with additional soil to prevent injuries that could occur if someone tripped in one of these holes.

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