A Gasoline Spill On Grass And Lawns? How To Fix It!


It’s Saturday morning and you decide to bring out your lawnmower so you can give your yard a little touch-up. As you raise your canister to fill up the machine, it slips and a considerable amount spills into the grass below! You’re no chemical expert, but you’re pretty sure that is not a good thing. What can be done?

Gasoline spills on grass will kill all grass, plants, or weeds in the area. The soil too will become tainted by the fuel and will need to be neutralized or replaced. Spilling gas on your lawn on purpose could bring legal troubles and is not a recommended way to kill grass or weeds.

That is precisely what we will be addressing in today’s article. We will talk about the various ways gasoline may spill onto your lawn, as well as the impact once it does. We also touch on the effects on soil and, finally, how to undo this whole mess.

How Gasoline Spills On Grass

Apart from the dropped canister scenario described in the introduction, there are quite a few ways gasoline can wind up in your lawn.

  • The most common problem is a leaky lawnmower.

Your mower may run into some problems that cause it to leak fuel.

One particular problem that affects most engines is the dislodging of the float bowl in the carburetor, which is supposed to block off fuel from overflowing.

The gasket that runs along the inner edge of the carburetor can also be worn out, which can cause leaks.

You can correct the float bowl’s positioning by removing any blockages between the carburetor needle or the seat, or by replacing the needle seat itself. The latter solution is specifically for Briggs & Stratton or Tecumseh engines. 

In the case of a worn carburetor gasket, you will have to find and install a replacement. 

Other causes of mower fuel leaks include:

  • Compromised fuel line

Leaks in the fuel line can come from worn material or loose connections. These may be slow trails down the side of the mower or faster drips.

These types of leaks can add up to a large amount of fuel in a short amount of time. Weekly maintenance should include checking the fuel line for any weak areas.

  • Damaged fuel tank

This can be from normal wear and tear over years of use, damage from collisions or falling limbs, or it could be from rust and lack of routine maintenance.

Holes or cracks in the fuel tank will more than likely leak out the most amount of fuel of any of these issues. This too should be an area checked during routine scheduled maintenance.

  • Damaged primer bulb

Primer bulbs are the soft, usually rubber ball located on the side of the mower. They are used to infuse gasoline into the carburetor so the engine will start properly.

Because they are made of soft material they can develop cracks after years of use or be damaged by hitting or rubbing against objects while mowing. These will more than likely be slower leaks and issues should be noticed rather easily as starting the mower requires their use each time.

Whatever the cause, make sure to get it fixed for the good of your mower…and your lawn.

One thing you could also do, to avoid accidental spills, is re-fuel your mower and other power tools while they are on a paved surface like your driveway. This may sound obvious, but you would be surprised at the professional lawn crews that forget that they parked their trailers on grassy surfaces and cause dead spots in the grass.

You might also want to head to Amazon and get a dripless spout for your can.

Will Gasoline Kill Grass And Weeds?

Unfortunately, a gasoline spill means certain death for any grass or weeds it comes into direct contact with. Some people may intentionally pour gas onto weeds as a way to get rid of them for good.

However, pouring gasoline into the ground intentionally may land you in hot water with the authorities.

Gas Kills The Leaves, Roots, And Stems Of Grasses And Weeds

As you know, gasoline releases some pretty noxious fumes. When plants (including grass and weeds) are exposed to gasoline and its fumes, their cells are ruthlessly ravaged and broken down. Grass quickly loses color and gets shriveled and dried out, like it has gone for weeks without being watered.

Essentially, grass and weeds are “burnt” upon exposure to gasoline and its fumes. The time it takes for the plants to die depends on the amount of fuel spilled, as well as how widespread the spill is. It can take anywhere from a few seconds to a couple of hours for total “leaf kill”.

Gasoline Can Also Ruin The Soil For A Time

In addition to the direct impact gasoline has on grass and weeds, there is an indirect effect. Gasoline can also impact the health of the soil, which will impede the development of plant life in that soil for a while.

Microbes and other soil organisms carry out various functions that add nutrients that are vital for plant life. Countless species of bacteria, fungi, algae, as well as earthworms, and other grubs, are essential parts of this ecosystem.

They help speed up the decomposition of dead matter, as well as its subsequent conversion to essential nutrients like nitrogen.

Unfortunately, due to a lack of a protective cell wall, these microbes are often more vulnerable to the effects of gasoline than plants. Those that escape death may still be severely weakened and rendered useless. When this happens, the soil’s nutritional content takes a severe nosedive.

If you would like to read more about grass then read my articles here…

How Long Does Gasoline Stay In The Soil?

As we’ve already seen, gasoline can also seep into the ground surface and contaminate the soil. 

The good thing is that most of the gasoline will evaporate as fumes before serious seepage can occur. However, gas can still infiltrate the soil and remain there for quite a while.

Residual gasoline can remain in the soil for several days to over one month. This depend on the volume of gasoline involved in the spill. Fumes from the spill can remain in trace amount up to two months later. Rain or rinsing the area with water is very little help.

Some of the best home remedies for gas and oil spills is cat litter. It soaks up liquids fast and hold them away from surfaces you are trying to protect.

The downside to using this in a grassy spot is then collecting it after it has leached the fuel from he area.

Expert Tip: If you are needing to soak up a spill with cat litter and are at a loss as to how to then collect the litter from the grassy area, they have a tool for that! A shop vac is the perfect remedy for your cat litter collection problem. It will leave your grass in tact and collect all of the fuel soaked granules.

How Do You Neutralize Gasoline Spills?

Luckily, the effects of a gasoline spill are not permanent. The gasoline will go away eventually, meaning you don’t have to do anything. It may take a little longer for the grass to be fully restored to its pre-spill state. 

However, you can accelerate the recovery process by following a few simple steps.

  • The first step is to contain the spread of gasoline.

The best way (even better than cat litter) to do this is to immediately pour pit sand on the affected area. Sand is much more absorptive than the soil typically found under a lawn. The sand will absorb a lot of the gasoline and minimize seepage into the soil below.

The sand’s absorption will also buy you enough time to effectively rinse off most of the gasoline. Run a hose on the spot for 10-20 minutes until the sand is completely washed away. 

Unfortunately, the grass on the spillage spot will probably be dead already, which will result in an unsightly patch or even several patches of lifeless grass.

  • The next step is to mow down the dead grass and, using a soil plug tool, extract soil samples.

Use your nose to check for any lingering gasoline smell and measure how deep it goes. If, for example, the smell of gasoline stops at the 3-inch mark, you will have to dig up 3 inches of soil and replace it with sand and a new layer of topsoil.

Again, the sand will play its absorptive role while acting as a buffer between the topsoil and any residual gasoline. Pat down the soil to make it level with the surrounding ground surface. Add a little fertilizer and moisten the soil with a sprinkler. Do not wash the topsoil away.

  • The next step is to get grass growing again.

If you have a runner grass species like Bermuda grass or Kentucky bluegrass, you can pick up some runners (stolons) from other parts of your lawn. Be gentle with this to ensure you pull out the stolons with as many roots intact. 

Place the stolons on the moist patch of soil and, with time, they will take hold and connect the patch to the undamaged parts of your lawn.

If you have a non-runner grass species, you will have to use grass seed. Scatter the seeds onto the patch, and gently work them into the soil. You can add a bit of straw to serve as the mulch. 

Once the runners take hold (or the seeds sprout into shoots) add a bit more fertilizer and continue monitoring until your lawn is back to its original state!

Final Touches On Gas Spills On Grass…

Gas spilling on a lawn will kill everything it touches. The soil will also have to be dealt with and rejuvenated. Accidents can be prevented by mower maintenance and ensuring refueling happens over paved serfaces.

With time and patience, spots killed by gasoline will return to normal.

Purposeful pouring of gas on a lawn could break local or state ordinances and is rarely the right choice when killing weeds or grass is the goal.

To read more about grass and its care, see my other articles here…

Other References

https://archive.lib.msu.edu/tic/mitgc/article/197890.pdf

https://forages.oregonstate.edu/regrowth/how-does-grass-grow/developmental-phases/vegetative-phase/rhizomes-and-stolons

https://www.youtube.com/watch?v=COGfIGUAQ2s&t=237s&ab_channel=TheAverageLawnGuy

Mathew Booe

Mathew has worked in landscaping professionally for over 10 years. He is a grandpa and frequently interviews other experienced landscapers and lawn care experts who are also grandpas for these articles.

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