Motor oil does not fertilize plants, it will kill plants over time and transfer harmful chemicals to edible crops and livestock that consumes plants grown in soil contaminated by motor oil.
Oil should only be disposed of in designated areas, if motor oil is applied to plants they will die and it can also harm the soil microbes, beneficial insects and pollute groundwater.
The properties of oil make it harmful for plants and all living things in the soil. The oil coats insects and microbes making them unable to use oxygen.
Oil does exactly what you would expect it to do, it suffocates and kills everything it touches that needs oxygen. Do not intentionally apply motor oil to grass or other plants.
It may not be immediately obvious that the oil has touched the plants as the death will be slow, but it will kill the plant.
There are plenty of unconventional fertilizers like cornmeal, epsom salt, molasses, eggshells and coffee grounds, but any type of oil should not be applied to soil.
When choosing a fertilizer for your plants you should be sure to start with a soil test then apply fertilizer to create healthy balanced soil.
Is Motor Oil Good for Plants?
Motor oil is not good for plants. Motor oil contains the base oil and additives that improve the viscosity and help clean the engine. Used motor oil also contains metal shavings, dirt, barium and zinc.
It can also contain compounds that leak from the engine combustion chamber.
Motor oil is not beneficial for any plants. The additives are specially designed to help improve engine performance and are not designed or tested in the soil.
Oil has been well studied on its effect on groundwater. It is poison to the water supply and the life that exists in the water. This is a great reason to only dispose of used oil in designated areas.
Can You Put Motor Oil In the Yard?
It is illegal to pour motor oil onto the ground. The oil can leach into water, kill soil bacteria, insects and kill plants.
Motor oil that has been used should be drained into a clean container and disposed of at an oil recycling facility.
These facilities are often located at waste disposal sites or public dumps.
How Long Does Motor Oil Last In Soil?
Motor oil spills will render soil inhospitable to plants for many years if not treated. Soil that has been treated with biosurfactants that wash out the oil can be fertile in as little as a year. Colder locations take longer and bigger spills take longer than small amounts of contamination.
If you have a patch of land that seems unable to support grass or other crops it is possible that oil has been mixed in the soil.
One solution is to dig up the soil and haul it to a landfill or public dump. This is a common practice when large spills take place at railroads or other remote locations, but it is very hard on the environment.
Gentler methods are being developed to remove the oil from the soil without removing the soil.
Biosurfactants are substances that can separate the oil from the soil so it can be collected and recycled. They are often the first step in treating large oil spills.
You can then treat contaminated soil by amending the soil with nitrate and phosphate fertilizer which will support bacteria and fungi that help break down the oil in the soil.
This process can be effective in a short time if the temperature is above freezing.
How Does Motor Oil Affect Plant Growth?
Motor oil kills established plants slowly by impeding their ability to absorb and use oxygen.
Motor oil does not burn leaves or immediately discolor leaves or stems like strong fertilizers or gasoline, but it will still kill the plants over time.
Oil on leaves can discolor them in high temperatures of direct sunlight by cooking the leaves.
Is Oil Toxic To Plants?
We all know that plants use photosynthesis to produce their own energy. This process requires the plants to exchange gasses like oxygen and carbon dioxide. If the leaves and stems are covered in oil they become clogged and cannot use the air.
Oil is incompatible with plant life. Plants that have been saturated in oil cannot photosynthesize.
How to Dispose of Used Motor Oil
So, now that you will not be pouring the oil out on the ground, where should it go?
Collect motor oil in a clean container and bring it to an oil recycling location. Many locations have regulations about what types of containers will be accepted, so consider calling ahead to be sure your collection container can be accepted.
If you find that oil has spilled, cover the spill with kitty litter immediately to absorb the oil. Sweep up the oil soaked kitty litter and place it in a garbage bag and bring it to the public dump.
Using Motor Oil in the Garden
Can I use motor oil as fertilizer?
Motor oil does not have any place in your garden soil. Motor oil should only be used as directed on the packaging and it should be disposed of at an oil recycling location.
Motor oil is toxic to plants and toxic in groundwater.
Why Is It Bad To Pour Oil On the Ground?
Motor oil is not the same as the oil that is drilled out of the ground. Motor oil may be made with crude oil and additives or it may be completely synthetic.
The additives in oil are not tested for or intended to be mixed with soil. The additives are designed to help keep the oil flowing at a wide range of temperatures and to help clean the engine.
These compounds break down and mix with metal shavings, engine blow by (chemicals from the engine combustion chamber) and dirt. This makes it even more toxic in the soil.
When draining oil be sure to collect it in a clean container and bring it to an oil recycling location. If you are not sure where it can be recycled you can phone a local mechanic or oil change location and ask for advice.