Will coffee grounds kill grass, is something coffee lovers ask us all the time in worry and anticipation. Coffee has so many uses and beneficial aspects when it comes to grass and lawn care.

Complete Answer of Coffee Grounds Kill Grass

We went through many research papers while combining our lawn maintenance experiences to develop this guide. Read and go through it to learn the answer to your question and other uses of coffee on the lawn.

Will Coffee Ground Kill Grass?

No, coffee grounds will not kill grass, they can be used as fertilizers providing a source of nitrogen, and raising the acidity of the soil. In addition, they would even aerate the soil, and providing pest control of the grass.

– Source of Nitrogen

Coffee releases nitrogen in the soil, but is not a good source. However, it is also a very abundant source of phosphorus, potassium, magnesium, and copper. Your grass needs all these trace elements to boost its growth and turn thick and vibrant, and of course it will thrive. 

Coffee grounds is one of the most effective natural fertilizer you have stored in your pantry. It breaks down slowly over some time in the soil and releases many important nutrients that help the grass grow.

Unlike synthetic fertilizers, coffee as a grass feed is much safer and will not harm the grass, no need to water it down or dilute it before use. It acts as a slow-release fertilizer that takes some time as it breaks down and releases nutrients slowly into the soil. You will not get to see instant benefits, but its effects are slow but long-lasting.

– Raising the pH

Having a pH of around 6.8, used coffee grounds will not affect the soil pH negatively. Luckily, this is the pH at which the grass thrives the most. If your soil is acidic, add used coffee to help raise its pH by two to three points.

Coffee Grounds Raise Soil pH

Acidic soil-loving plants like hydrangeas, rhododendrons, radishes, lily of the valley, and blueberries love it when fresh coffee grounds or freshly brewed coffee is mixed with their soil. 

– Aeration of Soil

Earthworms love coffee as well and increase within soil fertilized with it, and they will be the ones to thrive and aerate the soil of your grass lawn.

You might think this is not such a good thing. Think again! Earthworms are most beneficial for the well-being of your lawn and contribute to improving air circulation and the aeration of the soil. 

– Pests Control

Harmful pests you want to keep away from the grass, or other plants are repelled by it. Larger-sized coffee grounds are abrasive, and their texture greatly irritates slugs and snails, and they will no longer lay their eggs and hatch their larvae in your lawn. 

Start outlining your lawn with such grounds for a week, and these pests will stop coming to your backyard. You can mix other abrasive elements like crushed eggshells to make a more effective mixture.

As the coffee is brewed, the brewing process removes about 70 percent of caffeine from coffee, making it much safer for grass and plants that like neutral to alkaline soil conditions, and this would be part of the pest control process of this fertilizer.


How To Use Coffee As a Fertilizer?

Use coffee as a fertilizer by checking the soil acidity first, then you may want to dilute it in some water and sprinkle it around the lawn. In addition, you can even mix it with some organic compost, and even with nitrogen rich fertilizer.

– Testing the Acidity

When using fresh coffee, you better use a litmus paper to check the pH of the soil beforehand. Put a spoonful of soil in water and litmus paper in it.

Adding used coffee would be a better option if the soil already comes out slightly acidic or neutral.

Testing the Acidity of Soil

You can go for both used and fresh coffee, but the only difference is that fresh coffee is a bit acidic.

You need to apply coffee as fertilizer every month or every two months for the best effect. When the grass is undergoing its period of dormancy, there will be no need to fertilize it.

– Sprinkle

Fresh coffee has a higher percentage of caffeine than used coffee. This caffeine is not beneficial in large quantities. It also makes fresh coffee acidic, with the ability to lower the pH of the soil.

Fresh coffee grounds can be bought easily and crushed into grounds at home. You can also combine watering and fertilizing into one activity. Add approximately 500 grams of coffee in 20 liters of water, and use your sprinkler to water the entire lawn evenly and deeply. 

The laziest among you can sprinkle the grounds over the soil’s surface and wait for the earthworms to dig them deep into the soil. Rake the ground and spread it on the top one to two inches of soil if you want faster results. 

If you don’t own a sprinkler or a rake, then another method is to drill holes a quarter of an inch wide at the bottom of a plastic bucket or container. Pour ground coffee into this bucket and move across the lawn in straight lines, so no place is left unfed.

However, you must be very cautious because fresh coffee should also be kept well away from seeds and newly germinated grass seeds, as it has the potential to hinder their germination and growth. This would harm the process of their strengthening and thriving.

– Mixing With Compost

Adding coffee to your compost is a better way of adding nutrients to the soil. Using compost is one of the best ways to improve grass and help to neighbor plants grow. Technically, compost should be made of an equal ratio of greens and browns. 

In your compost you would have crushed eggshells are rich in calcium, phosphorus, and a small amount of nitrogen. They are best used for keeping larger pests like slugs away, but over time they break down and release nutrients in the soil in addition to the grounds, of course.

Mixing Coffee Grounds with Compost

The browns comprise pines, needles, dry leaves, twigs, paper, etc., whereas the greens comprise leaves, fruits, and vegetables. Add coffee grounds in one part to such a pile of compost and allow it to rot fully. 

Turn your compost pile every second to a third when the temperature deep within the pile reaches 160 degrees Fahrenheit. Once your compost starts smelling bad, this is when you know it is ready. 

Spread your homemade coffee compost over the surface of the lawn soil and use a spreader or a rake to mix it in superficially. Your lawn will stink for a while, but the results will be amazing. 

– Mix With Nitrogen Rich Fertilizer

You can add your stored coffee grounds to a commercially made nitrogen-rich fertilizer. Coffee will help your grassroots absorb nitrogen much faster and more effectively. Just dampen them a little because dry grounds will only work slowly. 

Microbes in the soil convert nitrogen in the soil to a form that the grassroots find easier to absorb. These microbes love coffee and increase greatly in its presence.

We mostly pour diluted liquid fertilizer over the lawn, but when coffee is added to it, you need to mix it in the ground. Ground coffee exposed to the soil becomes dry and hardens up. This layer hinders the soil from being watered adequately, so you should not allow it to form.


– Can Coffee Grounds Be Used To Kill Weeds?

Yes, coffee grounds can kill weeds, especially when applied at the start of their germination period. Coffee has allelopathic properties, which means that it can suppress the germination and growth of certain seeds and roots. Regularly applied to a lawn will kill weeds and prevent weed germination while not harming the grass.

– Can I Kill Ants Using Coffee Grounds?

Coffee grounds do not kill ants per se, but they dislike their texture and stay away from them. If you would like to keep ants away from someplace, sprinkle some fresh coffee grounds there.

Coffee Grounds Can Not Kill Ants

Both the texture and the rich scent of these grounds will repel ants. If you want to kill ants, then mixing ground coffee with hot boiling water is a better option, although we do not really cannot advocate such cruelty.

– Does Coffee Ground Harm Some Plant Types?

Because of their growth-suppressive properties, coffee beans harm certain plants like ryegrass, Bermuda, and tomato plants.

It does not allow the seeds of these plants to germinate fully, nor does it allow their roots to absorb nutrients properly. Fresh coffee grounds make the soil slightly acidic, harming plants that prefer slightly alkaline soil.

– Are Coffee Grounds Attracting Rats To My Lawn?

No, coffee grounds are not attracting rats to your lawn. Their smell is unfavorable to rodents’ sharp senses and repels mice and rats away. 

– How Often Is It Okay To Use Coffee Grounds On Grass?

Used coffee can be applied safely to your lawn grass every week. The recommended practice is to stick to a monthly coffee-feeding regime. Fresh coffee tends to be acidic with a high caffeine content, so it should be used only on acidic soil-loving grass and once a month.


This article taught us that coffee grounds do not kill grass but it helps it thrive instead.

To conclude, some other useful take-home points about coffee use on the lawn are given here.

  • Coffee is a useful fertilizer and can be added to the soil in ground form or mixed with water.
  • We prefer coffee over fresh one because it has 70 percent less caffeine and is also not acidic.
  • You can use fresh coffee for plants that like their soil to be acidic.
  • It is possible to mix ground coffee with nitrogen fertilizer or homemade compost to enhance its properties.

Instead of throwing away old coffee grounds, it’s time you start collecting them to be used as a grass fertilizer every month. In just a few months, you will see how rapidly your dull lawn transforms into a lush green carpet.

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