Does Roundup Kill Grass?

Effect of Roundup on Grass

For homeowners who take pride in maintaining a verdant and weed-free lawn, Roundup has become a household name. This glyphosate-based herbicide works by inhibiting the activity of an enzyme that is essential for plant growth, making it highly effective at killing weeds.

However, the question on many people’s minds is whether Roundup can kill grass too. The answer is more complex than a simple yes or no, as there are several factors to consider.

In this article, we’ll explore the science behind Roundup, its impact on different types of grasses, and alternatives to consider if you’re looking for a safer way to maintain your lawn.

Understanding How Roundup Works

Roundup is a glyphosate-based herbicide that works by inhibiting the activity of an enzyme called EPSP synthase, which is responsible for producing certain amino acids in plants. These amino acids are essential for the growth and survival of plants. By inhibiting this enzyme, Roundup blocks the production of these amino acids, leading to the death of the plant.

Glyphosate is absorbed through the leaves of the plant and travels down to the roots, killing the entire plant systemically. The speed at which Roundup kills weeds depends on various factors such as temperature, humidity, and the type of weed.

Roundup and Grass

Now let’s talk about the million-dollar question, does Roundup kill grass? The answer is yes, Roundup can kill grass, but it depends on several factors. Roundup is a non-selective herbicide, which means it kills any plant it comes into contact with, including grass. However, Roundup only kills actively growing plants. So, if you spray Roundup on dormant or stressed grass, it may not have much effect.

The effectiveness of Roundup on grass also varies depending on the species of the grass. Some grasses are more resistant to Roundup than others. For example, Bermuda grass is relatively resistant to Roundup, while Kentucky bluegrass is highly susceptible.

Additionally, the timing of Roundup application is crucial when it comes to killing grass. If you apply Roundup at the wrong time, it may not kill the grass completely, and you may end up with patchy areas of dead and live grass.

Safety Precautions

When using Roundup or any other herbicide, it’s essential to take safety precautions to protect yourself and others around you. Here are some safety tips to keep in mind:

  • Follow the label instructions and choose the correct Roundup product for your needs.
  • Apply the product carefully, targeting only the unwanted weeds and avoiding contact with desired grass and plants.
  • Use the recommended application rate and avoid using excessive amounts, which can damage the surrounding plants and soil.
  • Apply Roundup on a calm day to prevent wind from carrying the herbicide to nearby plants that you do not want to be affected.
  • Keep in mind that some grasses and plants may be resistant to Roundup, while others may be more sensitive to the herbicide.
  • Wear proper protective clothing, such as gloves and goggles, to minimize direct contact with the chemical.
  • Keep pets and children away from treated areas until the herbicide has fully dried and the risk of exposure is minimized.
  • Store Roundup in a secure location away from children and pets to prevent accidental exposure or ingestion.
  • Dispose of any leftover Roundup and its container according to local regulations and guidelines.
  • Remember that herbicides should be used as a last resort, and consider alternative methods of weed control, such as hand-pulling, mowing, or using organic weed control methods.

Alternatives to Roundup

If you’re hesitant to use Roundup to kill weeds in your lawn, there are several alternatives you can try:

  • Hand-pulling: While it may be time-consuming, hand-pulling weeds is a safe and effective way to get rid of weeds without using herbicides.
  • Organic herbicides: There are several organic herbicides available that can kill weeds without harming grass. Some examples include vinegar, citric acid, and corn gluten meal.
  • Pre-emergent herbicides: These types of herbicides prevent weed seeds from germinating, so they’re only effective if used before the weeds emerge. They’re a great option for preventing weeds from growing in the first place.


In summary, Roundup can indeed kill grass when applied, but its effectiveness depends on various factors such as timing, grass species, and growth stage.

To protect your grass and other desired plants, it is crucial to follow the label instructions, choose the right product, and take necessary precautions during application. Additionally, consider exploring alternative weed control methods to reduce reliance on chemical herbicides.

Ultimately, the choice of whether to use Roundup or not comes down to personal preference and the specific needs of your lawn.