There are over a dozen ways to kill a stubborn tree stump. If you don’t, the roots may put off suckers and continue to thrive. Blowing them up is dangerous, and grinders are expensive.
Sadly, natural decomposition can take a decade or more, depending on the density of the wood. What about killing tree stumps with motor oil?
Motor oil by itself will not kill a tree stump, however motor oil is flammable and can be used to burn the stump. Using a drill with a 1-inch drill bit, drill 45-degree angle holes evenly around the stump. Poor 2 tablespoons of motor oil into each hole using a funnel. Place some kindle on top of stump and light on fire.
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How To Kill Tree Stump With Motor Oil – Step By Step
Killing a tree stump with motor oil is not the best plan. However, since motor oil is flammable, you can use it to burn out the wood, which will kill the tree. Remember that motor oil fires are a significant pollutant.
The steps below are an example of how to use motor oil to kill a tree stump:
- Collect your materials. You will need a drill with high torque and a long, one-inch drill bit to reach deep inside the stump, motor oil, a funnel, some form of kindling, smaller sticks and twigs, and matches or a lighter.
- Drill holes evenly around the stump about three inches from the outer bark at three to five-inch intervals. You’ll want to drill in at a forty-five-degree angle. Place another hole in the center. The number of holes will depend on how large your stump is. For tiny trees, a single hole in the middle is enough.
- Put your funnel in a hole and pour in a couple of tablespoons of motor oil. Then, working your way around, do the same with all the rest of the holes.
- Place your small sticks and twigs on top of the stump and add kindling to get the blaze started.
- Finally, light your kindling and step back to a safe distance.
Never leave a burning fire unattended. Negligence can rapidly result in a much larger blaze, and no one wants to risk burning down their home or land.
It would be best if you kept a couple of buckets of sand or an ABC-rated fire extinguisher handy in case you need to put your fire out.
As Mobil points out, you should read the directions before you start any fires as an emergency is the worst time to start learning how to use this vital tool.
Unfortunately, like other oils, you cannot use water to douse the flames. Doing so can cause a fireball-type explosion, and you will probably get injured.
Build A Fire Without Motor Oil
A safer and smarter way to burn out your tree stump is to skip the motor oil entirely. You can use fire to kill a tree stump without the unnecessary added risk and toxicity.
Plus, cutting the motor oil not only reduces the pollution from the smoke but also changes that fire from an oil/grease fire into a normal wood fire that you could put out with a hose.
Not adding oil to your fire reduces the chances of flaming, boiling oil exploding, and spreading fire to other areas.
Avoiding this is a significant benefit, especially since you will probably be nearby. You can use a tree stump as a natural fire-pit-type blaze.
Moreover, you can put the fire out, and when the stump is dry again, add a small log and continue the burning process until the whole stump is eventually gone.
Burning the stump out will leave you a nice, natural firepit. All you have to do is fill it with sand and then place rocks around the edges.
Or, if you prefer, fill the hole where the tree used to live with soil to smooth the ground back out instead.
Will Used Motor Oil Kill Tree Stumps
Used motor oil contains numerous impurities from running through your cars’ engine. Although some of these impurities might damage a tree stump very slowly, there’s a much better use for used motor oil. Recycle it.
Refiners can remove all the problematic debris and buildup so more cars can use the oil or go into other new products.
How Fast Will Motor Oil Kill Tree Stumps
Motor oil does not kill tree stumps, or at least not quickly. If you doused an entire live tree in motor oil, then in addition to having a miniature ecological disaster on your hands, you might smother the tree.
Leaves need to breathe to expel the waste-oxygen that animals and humans require to stay alive.
However, it would still be a prolonged decay process. The oil would also effectively seal out natural decomposers that would otherwise break down the dead tree over the next several years.
Preserving the wood with toxic, flammable oil is the last thing you want to do if you plan to get rid of a tree stump.
How Much Motor Oil Is Needed To Kill Tree Stump
You don’t need any motor oil to kill a tree stump. It is a terrible idea because the oil preserves the wood. If you have carvings, wooden handrails, or hardwood flooring at home, then you know that oil and wax are the ideal preservatives for these lovely surfaces.
More importantly, using a toxic oil that you could easily recycle instead is bad for the environment.
BendOregon.gov aptly explains this with the simple phrase “You dump it, you drink it.” Pouring oil on a tree stump will eventually lead to that oil reaching the ground.
Once motor oil sinks into the soil, the next rain will help wash it deeper into the earth.
Eventually, this will lead to motor oil reaching the water table, where many local water companies and residents with wells get their drinking water. Instead of poisoning a tree quickly, you are poisoning people slowly.
Helpful Tips To Know About Killing Tree Stumps With Motor Oil
Even without motor oil, some trees put off toxic smoke when you burn them. It’s important to know what species you are working with and wear PPE to remove or burn potentially harmful wood.
Here are more helpful tips to know about killing tree stumps with motor oil.
- Decomposers in the soil like fungi will naturally break down a tree stump over time. However, to do so, they need moisture and oxygen.
- Motor oil is an excellent barrier that keeps your car parts from scraping across one another. On a tree stump, it will form a similar seal. The molecules in the oil are too close together to allow other molecules to pass through them.
- All oil is hydrophobic, so it locks out water. This method will stop the decay process and give your stump a dark glossy shine. In short, you will have a greasy stump for years to come, and it won’t even make a good seat because it will stain your pants and possibly cause an allergic reaction when the motor oil seeps into your skin.
- I feel this bears repeating. Please do not pour motor oil over tree stumps. Not only is it harmful to the environment, but the only way the oil will help get rid of a tree is when you light it on fire. Doing so is more dangerous and challenging to manage than lighting an oil-free fire. This is not a good way to reuse old motor oil.
Final Thoughts
The internet is full of outstanding, helpful life hacks that can save you a lot of time and trouble but using motor oil to kill tree stumps is not one of those hacks.
Much like the videos of people cutting open batteries to find smaller batteries inside, this is dangerous, may cause injury, and it’s not going to work the way you think.
This idea may even have started as a hoax. If you want to burn a tree stump, do it the usual way. Likewise, if your goal is to preserve the tree stump, stick to a regular wood polish or use carnauba wax instead.
Both options are less toxic, and they won’t damage you and your clothing if you sit on them. Recycle your used motor oil!