What Kills Grass? - 8 Methods to Eliminate Unwanted Grass

If you maintain a yard long enough, there will likely be a time when you need to kill grass in some areas of the landscape. This may mean eliminating a small section that has become as minor problem or killing off the entire lawn for a renovation project.

Fortunately, there are several ways to kill grass beyond chemical grass killers that are often the first choice of homeowners. While commercial grass killers are one of the most efficient methods to eliminate grass, we encourage you to consider the other alternatives we have outlined below. Without further delay, here are 8 effective methods to kill grass.

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8 Ways to Kill Grass

Chemical Grass Killers

Products such as Roundup and RM43 are extremely effective at killing grass. You simply mix (if required) and spray the chemical on the grass you want killed as directed on the product label. You should start to see results in a couple of days, but it generally 7 to 10 days to completely kill off the grass.

Be aware that there is controversy surround the ingredients. The active ingredient, glyphosate, was stated to be a probable human carcinogen by the World Health Organization (WHO) in 2015. There is a lot of debate on the true impact that these type of weed killers have on humans and the environment.

You may wish to come to your own conclusions on how harmful these products are to humans and the environment. If you decide to use a commercial weed killer, protect your body during use as advised on the label.

Vinegar

Vinegar can kill grass. However, the weak 5 percent acetic acid vinegar found in grocery stores is not very effective at killing to the root. You’ll have to use a vinegar with a higher concentration of acetic acid outside of the supermarket.

A product that many people have had success with is Green Gobbler Vinegar Weed & Grass Killer. This contains 20 percent acetic acid which is a high enough concentration of vinegar to kill off grass and weeds such as dandelions, clover, and dollarweed.

You may also want to consider this EcoClean 30% Pure Vinegar found on Amazon as a more powerful option.

Smother It

Grass will not survive if it is starved of water, sunlight, or oxygen. Smothering the grass with a thick layer of material such as cardboard or newspaper will kill it off. The newspaper should be about 6-7 layers thick and 1 layer of cardboard will do the trick.

The downside to this method is that the curb appeal of your home will be diminished from unsightly materials laying on the grass. Additionally, it may take 1.5 to 2 months to kill the grass this way. You may want to only use this method in out of sight locations if you are concerned about visual appeal.

Additionally, this is not a practical method for killing large areas of grass (i.e. a complete 1/2 acre lawn). Plan on using this for smaller areas such as a weedy 6 x 6 foot section of the lawn.

Solarization

This is similar to the above smother method but it uses a clear tarp that is 1 to 2 mils thick.

You mow the lawn that you want to kill at the lowest level. Then water the area for 15 to 20 minutes until the soil is well saturated.

The tarp can then be placed over the target area. Rocks or other heavy objects can then be placed on the edges to keep the tarp from moving.

The sun will heat the soil to a high temperature and kill the grass as it shines through the clear tarp. This method should be completed in the summer when the sun is creating the harshest conditions for your lawn.

You will be able to monitor the progress through the clear plastic. However, this method will take some patience. It generally takes 1.5 to 2 months to kill off the lawn.

Why use a clear tarp? A clear tarp acts like a greenhouse to raise the soil temperature. As the University of Illinois explains, a black or colored tarp will not heat the soil sufficiently.

Boiling Water

Yes, pouring boiling water on grass will kill it. However, we only recommend this method for tiny areas. This is because you are going to need a lot of boiling water for it to completely kill off a given area.

The below video provides a good overview of the affect boiling water has on weeds. The impact on grass will be similar to the weeds shown in the video.

Credit: Christa McCourt

Manual Method

Digging up the grass manually is the best way to remove it without having to wait for chemicals or other methods to work. This Bully Tools Sod Lifter is a handy tool to properly gain access under the sod so that it can be lifted up. If done properly, the sod can be transplanted to another location, if desired, when using this method.

Admittedly, this will be hard, laborious work depending on the area you are wishing to remove. You can also consider using other garden tools such as a spade or shovel, but they generally will not be as effective as a sod lifter.

Power Equipment

A powerful rear-tine tiller or sod cutter can be rented from certain hardware or equipment rental stores to remove grass. The rental fee and fuel costs typically make these machines only practical for larger jobs such as removing a full lawn.

These will require a significant amount of labor to operate them. However, despite the labor, they will quickly dig up the sod and save an enormous amount of time over manually digging up the grass.

Salt

Salt spread on grass prevents the roots from obtaining water. It essentially dehydrates the roots causing the grass to brown and die. Simple table salt can be spread over the location you want killed. In a few days, the grass will be dead.

However, the problem with salt is that it does not break down. This means that if you intend to regrow grass or other vegetation in the salted area, it will likely not grow for some time. To be safe, only use salt where you do not wish to ever grow grass or plants again.

Why Kill the Grass?

Grass is often a desirable part of landscaping that adds to the appeal of a home. However, there are reason why you might want to get rid of it. Here is why you might consider killing your grass:

Weeds – If your lawn is overrun by weeds, it is sometimes best to kill off the existing lawn and start over by seeding or sodding. In lieu of killing the entire lawn, an often better course is to try to only kill the weeds using products like Scott’s Turf Builder Weed and Feed or Weed B Gon that target the weeds but do not kill the grass.
Unfavorable Existing Grass – Some types of grass are more appealing than others. Additionally, some grasses are much more maintenance friendly (i.e. need less water). Killing the existing grass is the first step to creating a lawn upgrade.
Water Savings – While lawns are a popular feature of American homes, they require a lot of water to maintain their beauty. Many people, especially in southern climates, opt to do away with their lawn for a landscape that require little or no water.
Money Savings – Costs such as fertilizer, water, gas, electricity, and professional lawn care add up during the year. Some people opt to kill their grass for a more budget-friendly landscape.
Unwanted Growth – Grass does not always stay neatly in its designated area where it is intended to grow. It can make its way into sidewalk cracks, garden beds, and other unwanted areas. Killing this rogue grass helps maintain a peak yard.
Change of Landscape – Grass is often killed to establish something new. A new flower garden is one example where someone might kill the grass to start a new landscaping project.