The Effects of Dish Soap on Lawns — Will Dish Soap Kill Grass?

Last Updated on September 1, 2021 by Grow with Bovees

Taking care of your lawn is perhaps the most important part of upkeep to make your yard look lush, and keep it free from harmful pests and weeds.

Even though there are myriad different solutions to maintain a lawn, some avid gardeners explore rather odd lawn maintenance DIY techniques, with dish soap trending as the latest one.

So, the big questions are is does liquid dish soap actually work on grass? Short answer is — yes dish soaps can be used on lawns, but there’s a right way to use it!

That said, here’s the lowdown on if you should dish detergent, and how it may be beneficial to your lawn.

What Exactly is Liquid Dish Soap and its Ingredients?

Dish soap is a generic name for several different liquid soap products used to wash dishes.

Leading brand names of dish soap include Dawn, Joy, Palmolive and Sunlight, which are also referred to washing-up liquid, dish washing detergent and dish washing soap.

The words soap and detergent are often used interchangeably, but scientists claim that they are chemically quite different.

Soaps are cleaning solutions made from natural fats and oils, whereas detergents are made from synthetic chemicals called surfactants, and are designed to break down the organic matter residue from food.

Even though both soaps and detergents serve as cleaning solutions, they use different chemicals for the task.

Insecticidal Soap vs. Dish Washing Detergent

Insecticidal soap isn’t a new pest and weed control solution to the insect killer scene, but in fact has been used for over 200 years as a way to kill pests.

This type of soap is one of the oldest and preferred insecticides used in the old days, but has fallen off the radar in recent times, due to the conception of much stronger and toxic harmful chemicals.

But since there is a surge today in organic gardening techniques, insecticidal soaps are making a major comeback.

Insecticidal soaps are real soaps, and not detergents, as they contain a mix of sodium hydroxide or potassium hydroxide and fats.

Insecticidal soaps are specially formulated to curb infestations of pests and insects in lawns and gardens.

If you take a closer look at the chemicals in Dawn dish washing liquid, it contains sodium lauryl sulphate, sodium chloride, lauramine oxide, and much more.

This implies that dishwashing liquid is not a “soap” per se. but is a dishwashing detergent.

Will Dawn Dish Soap Kill Your Grass?

As mentioned earlier, diluted dish soap is not a true soap, but in essence a detergent. It is an effective choice for removing grease and rest of the yucky stuff from dishes, but is a bit harsh to use on plants.

When you spray dish soap such as Dawn on your plants, it washes away the natural oils and waxes that all plant leaves are coated with.

These natural oils and waxes work to protect the leaves, and when removed, leave a clear path for pathogens to infect the plants.

The sole idea of spraying dish soap on your lawn stems from the fact that it can indeed be effective at killing insects, and even certain weeds.

But Dawn dish soap when used on your lawn also dries up everything that it comes in contact with — your plant leaves, and even grass.

The chemicals in Dawn dish soap may work miraculously for getting out tough grease and stains on your dishes, but can be detrimental to your healthy lawn plants and grass.

How to Use Dish Soap on Your Lawn Safely

Dish wash soap can cause damage to your plants and grass, but can also be used as a safe pesticide with less impact on your yard.

To create this safe dish soap solution, grab a cup of water, and add just a teaspoon of dish soap and vegetable oil.

Fill a spray bottle or garden sprayer with the mixture, and spray the areas of your lawn that are affected with pests and weeds.

The mixture must be sprayed directly over the pests for it to be effective. After you’ve sprayed the mixture, wait a few hours, and use your garden hose reel to wash your lawn thoroughly with water to get rid of the dish soap mixture, or else you risk shriveling your grass too.

Does Dish Soap Kill Grubs?

Grubs are the immature stage of several species of beetles and chafers, and can literally feast on the roots of your grass.

There are several commercial killers available to kill grubs in your lawn, but you can also use a homemade recipe with dish soap to kill the grubs.

When sprayed, Dawn dish soap smothers the grubs until they die. The grubs once in contact with the soapy solution suffocate and die within a few minutes.

You can make this homemade insecticidal soap solution by simply combining liquid dish soap and water as follows; three tablespoons of Dawn soap per gallon of water, stir well, and spray only over the brown patches of dying grass.

This homemade insecticidal soap requires a little time to take effect, so wait for roughly an hour, dig up the treated area, check for grubs, and if you notice any, repeat the process.

Does Dawn Dish Soap Kill Armyworms?

Army worms are a common pest that is found throughout the United States. They like to feed on grasses, mainly fescue, ryegrass and bermuda.

They are also partial to some vegetables, they love to suck the juices out of your onions, beans, beets, peppers and cabbages, so make sure to check out your vegetable garden for these pests.

The armyworm larvae hatch from eggs laid by adult female moths. The larvae can vary in color. Some are quite dark, almost black, where others can be dark green.

These caterpillars then spin cocoons around themselves where they will pupate into adults. Adult females lay more eggs which eventually join the army as new caterpillar pests.

The right time to treat for army worm grubs in the lawn is between spring and summer. In fact, dish soap has been proven to be one of the most effective ways to eliminate armyworm grubs from your lawn. Just mix it up in a bucket with water, and splash it over the lawn. After a short time, you should see the caterpillars emerging.

It works because it disrupts the cell membranes of grubs, which causes them to dehydrate and eventually die.
However, keep in mind that it takes several applications before the grubs start to disappear completely.

Will Soapy Water Get Rid Of Lawn Fungus?

Lawn fungi generally indicate that your yard has poor drainage, or is covered with too much shade. In which case, you could try using grass that is suited to shady areas, and check out our page on shade gardening in general.

Even though it is near impossible to get rid of lawn fungi completely, there are certain ways to control the issue such as with dishwashing liquid.

Mix three gallons of water with two tablespoons dishwashing detergent.

Next, prepare the area with the fungi infestation by digging 6-inch holes about 12 inches apart with a screwdriver or similar tool.

Spray the area with the dish washing solution to stop the growth of the fungi, a backpack sprayer can be used for larger areas.

For Moss

To get rid of moss, for every 1,000 square feet (ca. 93 m²) of lawn, make a solution of water and dish soap, using 4 ounces (0.12 liters) of dish soap per two gallons of water.

Final Thoughts On Dish Soap And Lawn Care

Dish soaps contain several chemicals that could be harmful to your grass, and favorable plants.

But on a brighter note, you can dilute dishwashing soap to kill insects and weeds with caution, as there is still a slight risk that you may cause your good grass to dry out.

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