What can you put on a tree stump to kill the roots?

Drill holes and either use rock salt or stump out

Drill holes in it and pour full strength vinegar in them. Will take a number of applications, but vinegar is cheap.

Good advice. Do it naturall.

A tree guy recently told me to use Brush Killer.

You can also use gasoline or table salt in the holes. It takes time but either will work.

If the stump is large enough and stick up above ground enough; you might be able to make something out of it. Just saw the excess and put it aside for later. Then try one of these: 1) Drill several medium to large holes deep into stump. Then pour salt peter(sodium nitrate) into each hole and fill up with water. It will take a while but it will go away.

2) Check hardware for liquid stump remover and pour that into holes.

3) If the stump is in a safe place; away from house, cars, utility lines, you could pour small amount of Kerosene, starter fluid for BBQ, or lighter fluid into the holes. Then set it on fire. I'd put a few candles in or near holes, light them, and get back. CHECK YOUR LOCATION TO SEE IF BURNING IS ALLOWED!

I have also heard people pour plain table salt, rock salt, or vinegar on them to dissolve.

Use this product and you should have success. Bonide

Begin by gathering a few supplies: a drill with a large bit or an ax, Epsom salt, water, wax, a tarp, and a shovel. Proceed to drill several 1-inch-wide holes in the stump's surface, including its aerial roots, ensuring each hole is placed at a distance of at least three to four inches. While six holes are sufficient, bigger stumps may require more. Ensure you drill down to around eight inches to allow for deeper salt penetration. Alternatively, you may use an ax to make hollows in the tree stump. Next, directly pour Epsom salt ¾ of the way up in the drilled holes and fill the rest with water to keep the salt moist. Then, plug the holes with wax. Additionally, cover the trunk remnant with a non-porous tarp to minimize rain and sun exposure so that the roots do not sprout again and the salt does its job of rotting the stump. Repeat the procedure every three weeks until the stump is dead, and dig it out using a shovel.

If you don't wish to strain yourself by drilling holes, you can use the soaking method to remove a tree stump. In a bucket, combine Epsom salt and water in a 1:2 ratio. Generally, soaking a single tree base requires two gallons of water and one gallon of salt. Pour this solution all over the tree stump and its largest exposed roots. After drenching the stump, cover it with an opaque tarp or a plastic sheet, and add a layer of mulch on top to weigh it down. You can also sprinkle a nitrogen-rich fertilizer around the tree trunk's base to further boost its breakdown. Repeat this method at least once a week and chip away at the wood as it decomposes. Finally, pull out all the stump remnants, especially the root system, when it completely dries out. After disposing of the stump, you can repurpose the space by adding soil and sowing grass or flower seeds.

Hi Laura, hope this helps you. Drilling holes into the stump will help the hot water kill deep and exposed roots. After you're finished drilling, carefully pour boiling water over the stump, making sure to cover the entire stump. The hot water will shock the system and begin the decomposition process using heat. Then you could pour some epsom salts in the holes and cover them ( to prevent them getting diluted by rain)to let them break down the stump.

Epsom salts

https://www.bobvila.com/articles/how-to-kill-tree-stumps/