Will coffee grounds kill grass?

I was chilling out with my girlfriend the other day in our garden, when something unusual caught my eye.

Our next door neighbour was spreading coffee grounds on his grass; he later explained to me that this is a great fertiliser for grass making it grow faster and keeping it away from fatal diseases. Can coffee grounds make a positive impact on your grass?

Let’s go through a bunch of key aspects of this grass maintenance method.

Do coffee grounds harm your grass?

The answer is No, not really. Sprinkling coffee grounds on your lawn is a great way to boost your grass and maintain it in good condition. However, using freshly ground coffee isn’t the best idea (although it’s a great natural method for killing weeds in your garden); it’s caffeine and acid that might dry up your grass. 

Instead, go for grounds you had just used to brew coffee.

About 80% of caffeine in coffee beans is removed during brewing, making used coffee grounds less acidic and just what the doctor ordered for your grass. As a rule of thumb, simply sprinkling your used coffee grounds on your lawn once a week is going to be enough to keep your grass healthy.

And of course, it’s wise to spread just small amounts, as big portions damage grass over time. 

How do coffee grounds make your grass grow?

Coffee not only can help us kick-start the day, but can also help your lawn look lively and healthy. Phosphorus and nitrogen are some of the coffee compounds that really benefit grass; these valuable nutrients are gradually broken down and absorbed by soil acting as a natural fertiliser that keeps your lawn in top condition for longer. 

Earthworms come into play consuming the coffee grounds and their movement creates air spaces (or aeration) that moisturises the earth which is conducive to your grass. 

Do freshly used coffee grounds are bad for your lawn? 

The good thing with freshly used coffee grounds is that they contain only around 20% of the caffeine as unused coffee, but sprinkling them on your lawn isn’t the best possible method. 

Ideally, composting freshly used coffee grounds and mixing it with other materials is going to bring the best possible results. 

Because they’re seen as a ‘green’ compost addition it’s wise to mix them with ‘brown’ ones including Fall leaves, pine needles and twigs. It’s vital not to add too much coffee grounds to your pile (preferably less than 50% of your green items) and water your compost regularly to ensure that the acid coming from caffeine has been reduced to its minimum. 

Once your compost is ready you can apply it to your grass.

Pros and Cons of sprinkling coffee on your grass

Let’s go over the pros and cons of sprinkling coffee on grass.

Pros

Insect repellent 

Although we humans love the aroma of coffee, snails and slugs just can’t stand it, so it works as a great natural repellent to keep insects away from your grass. 

The remaining caffeine in the coffee grounds helps to keep pests such as slugs and snails from the grass. The caffeine smell is disgusting to some of these animals, which works well in your favour during a barbeque cookout.

Stray animal repellent 

Similar to insects, cats simply abhor the aroma of coffee and since they have a strong sense of smell by spreading coffee grounds around you won’t see any cats treading on your lawn. 

It prevents fungus from your lawn

Who likes fungi hanging around on the corners of their wonderful lawn? To prevent such fungi all you need to do is sprinkle your grass with compost of coffee and you’re good to go; you’ll be able to flaunt your grass and show everyone you manage to keep it in excellent condition. 

Cons 

It can turn your grass into yellow 

If you spread unused coffee grounds or even freshly spent coffee grounds on your lawn, odds are that they will do some damage to your grass, blocking the soil from getting moisturised, making your grass dry and yellowish. 

It impacts your turf’s pH levels

Adding coffee to your lawn regularly has a negative effect on your turf. Because coffee is acidic it increases the pH over time causing you an unhealthy turf. To keep your pH levels between the recommended  levels (6.0 and 7.0 pH), it’s wise to apply coffee to your grass in moderation – balance is key. 

Will used coffee grounds damage your garden’s grass? 

As mentioned above, spreading spent coffee grounds isn’t as bad as using unused coffee, due to the caffeine levels that’s removed in the brewing process. It’s wise to go for composting your used coffee grounds to avoid any risk of damaging your lawn. 

Does spilled coffee damage your grass? 

It’s happened to me many times, walking onto my lawn carrying a cup of coffee filled to the brim and spilling coffee all over the place.

Has it happened to you as well? 

I need to kick this habit; brewed coffee is apparently harmful to grass due to its caffeine content. But it’s not as harmful if you have an established grass, but it kills newly seeded grass.

From now on I’ll have coffee only in the kitchen. 

Do coffee grounds keep weeds away?

Yep, it’s an excellent natural weed repellent. Real weed suppressants can be found in coffee grounds, especially when they are fresh coming out straight from your coffee maker. They raise the temperature of the compost mixture when added, hastening the decomposition process and killing weeds and any other kinds of pathogens. 

When mulching grass at soil level with compost mix, the heat rapidly destroys pathogens and weeds in their sprouting state. 

Plus, coffee grounds have allelopathic qualities that inhibit the weeds’ ability to germinate, causing them to perish at this stage – you have every good reason to use them to keep weeds away from your lawn, they cost you nothing and get the job done.

How to remove coffee grounds from your lawn? 

Whether it’s unused or spent grounds that you need to get rid of from your lawn it’s key to act fast so they don’t damage your grass. 

If it’s fresh coffee grounds you can just hoover or sweep them up and if they’re used you can just splash water on the area where the grounds are to spread them and reduce the caffeine concentration since water dilutes caffeine. 

Why are coffee grounds a great grass fertiliser?

They are great for a bunch of reasons:

• Unlike a chemical fertiliser, they damage the soil 
• They don’t cost you extra money to use them 
• They add the special coffee aroma to your garden
• They are easy to use and you don’t need any fancy gear to apply them on your lawn.
• It won’t take up too much of your time to spread them and you only need to do it once a week.

Wrapping it up

Since you now know one more way to use coffee grounds, go ahead and warn your family that from now on if they throw away coffee grounds you won’t buy a cake for them on their birthday.