It’s becoming more common for homeowners to find natural ways to maintain their lawns and manage problems in their yard. This includes using dish soap to get rid of pests. While this method can be effective, there are certain risks that come with using household soap on your lawn. Does dish soap kill grass? Yes, if you don’t use the proper amount regular old dish soap could kill the grass in your lawn.
This article was last updated on by Lawn Chick Owner Sarah Jameson
Article content reviewed for accuracy by Certified Horticulturist Nicole Forsyth, M.S.
Dish soap contains concentrated chemicals that are meant to remove food stains from dishes, breaking down oils and fats in the process.
If too much dish soap is used on your lawn, it will break down the oil-based tissue that your lawn grass needs to survive.
Without this tissue, your grass will turn brown and patchy. However, there are ways to use dish soap safely to effectively kill lawn pests without killing your grass.
The following article is a more in depth explanation of how dish soap can kill grass.
It also includes a few tips on how to use dish soap on a lawn safely, as well as how to repair grass that has been damaged by dish soap.
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How Does Dish Soap Kill Lawn Grass?
Dish soaps are made with concentrated chemicals that help break down food particles, particularly oil and fat.
Most plants, such as lawn grass, have oil-based tissue in their roots that helps them survive. The tissue is meant to help them retain moisture so that they don’t dry out after not being watered for a while or being exposed to sunlight.
When that tissue is destroyed by soap, your grass won’t be able to stay hydrated and it will dry out and die very quickly.
This effect is mainly caused by the chemical sodium lauryl sulfate (or SLS), which is a common chemical found in dish soaps.
Not all dish soaps have it, and even if they don’t have SLS as an ingredient, they can still kill the oil-based tissue if enough is used on the lawn.
If too much dish soap is used on a lawn, it can kill your grass within a day. Fortunately, there is a way to safely use dish soap for lawn maintenance.
Let’s get into that.
How To Use Dish Soap To Safely Kill Lawn Pests
There is a benefit to using dish soap to kill ants and other lawn pests naturally. Since there aren’t nearly as many toxic chemicals in dish soap as there are in some pesticides, it can be a great alternative if you have pets or children and don’t want to use a commercial ant killer on your lawn.
Dish soap is very effective at killing multiple lawn pests when used correctly, including:
Since dish soap can dissolve oils in plants, it can also dissolve the oils that are in some insect shells. This will cause those insect pests to dry out and die, effectively preventing an infestation.
It will also kill lawn grubs by suffocating them, only you will need to use a few more tablespoons to make the mixture thick enough to be effective.
Finally, dish soap can kill moss, weeds, and fungus by drying them out. But dish soap must be used sparingly.
The first thing to do before using soap on your lawn is to dilute the dish soap a small amount.
Dish Soap Lawn Treatment Recipe
In a bucket or a handheld sprayer, combine the following ingredients:
- One cup of water
- One teaspoon of dish soap
- One teaspoon of vegetable oil
Mix it all together thoroughly and apply it to the areas of your lawn that need it the most.
I recommend that you test this mixture on a small area of your lawn, especially if you’ve never used the dish soap method before. Just come back one day later and you’ll have a good sense of whether it will harm your grass.
Make sure to spray it on both sides of the leaves or the grass blades. Pests and insects usually hide their eggs or hide underneath plants, so spraying under them will help ensure you kill them all off.
Important Next Step Most People Skip!
After the mixture has been left on your lawn for about two hours, rinse it off with water. If you let it sit for too long, the mixture could soak into the roots and end up hurting your lawn rather than helping it.
I usually recommend that you apply this dish soap mixture once every 2-3 days until your pest problem is gone.
What About Weather?
I recommend that you apply the dish soap mixture on cool and cloudy days.
Applying it in sunny weather and temperatures that are over 90 degrees can lead to the mixture drying out, and it won’t really do anything for the lawn problems you’re trying to address.
Late in the day and early morning are the best times to apply the mixture to your lawn, and again – make sure you take a hose and water down the area about 2 hours later.
Tips To Repair Soap Damaged Grass
If you have dead grass because you used too much dish soap (or didn’t rinse the area after applying it), there are ways to revive your lawn.
First, hop into your time machine and make sure you didn’t spill un-diluted dish soap on your grass.
(just kidding – you probably don’t have a time machine either)
Water is your friend.
Water will help to dilute the soap and lessen its direct contact with the grass, so even if your lawn is starting to appear dead in an area where you spilled dish soap or used a natural pest treatment, water the area thoroughly … your grass may just be playing possum!
Soak The Area Thoroughly
Make sure to soak and rinse the area well, since the soap can stick to the waxy coating of your grass and eat away at its pest defense.
If your grass bounces back in a day or so you came to the rescue in time, but if dish soap has already killed your grass, there is still hope.
There are ways to repair a dead spot in your lawn pretty quickly. Here are your options:
Fresh Sod
The most popular method of repairing dead grass in your lawn is to lay down a piece of sod. Sod is essentially a slab of already grown grass that you can incorporate into your lawn.
Simply cut out the area of dead grass where you had the damage from dish soap and then replace it with a fresh piece of sod. You may be able to buy sod locally, but what I like to do is to find a section of my yard that is not very visible, and cut a piece of healthy grass out that fits the hole I created.
I’ll then swap the two pieces of turf, and sprinkle some seed in the less visible part of my lawn. It’s a free, quick, and easy way to repair a lawn area that has been killed by dish soap.
The new hole I created I fill with the damaged piece of turf (I turn it upside down with the dead grass buried). Water it well, use a rake to loosen the soil before sprinkling it with grass seed. Covering the seed with a light layer of peat moss to keep birds away and keep it moist.
Within a few weeks both areas of your yard will be beautiful and nobody will be the wiser.
Fertilize, Water & Seed
If you don’t want to cut a fresh piece of sod and replace that section of your lawn, simply water, apply some fertilizer and seed. It won’t take long to fix the dead patch that way.
This will take more patience, but it’s easy, and you can learn more about how to do this right here.
You should also avoid using dish soap on your lawn once the grass is healthy again. Look for other pest control alternatives.
One Last Thing (surprise)
Finally, and there is definitely irony in this, you can actually repair dead grass with some dish soaps.
If your soap includes phosphates, then a small amount of it could actually help make your grass green again.
Admittedly, this isn’t the method I recommend to green up your grass.
But if you’d like to try this method, fill a sprayer or a bucket with one gallon of lukewarm water and one teaspoon of dish soap that contains phosphates.
Mix it together well and spray the affected areas with a thin mist. You can apply fertilizer after a few hours have passed, and water your lawn. You can re-apply the mixture every 6 weeks until your grass is revived.
Does Dish Soap Kill Grass? You Bet.
Dish soap can be a healthier, more natural alternative to using pesticides to kill troublesome lawn insects. But like anything you apply to your lawn, you need to be careful.
The chemicals used in many dish soaps can quickly dry out grass and other plants. This can kill them, and make it difficult for them to survive.
Diluting dish soap with water or vinegar and applying it sparingly will help you avoid killing your lawn. You can dilute it using the recipe I shared earlier in this article, and it will still be effective at killing pests in your grass.
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-Sarah
