When you should (and shouldn’t) put used coffee grounds in your garden

Depending on how into gardening you are, you may be aware that putting used coffee grounds in your garden is a highly debated topic. Some people swear by using coffee grounds for growing plants, while others say it’s the worst thing you can do for your garden. So which opinion is correct, and how do you know which side to trust? How do you know if you should – or shouldn’t – put used coffee grounds in your garden? We’ve researched the pros and cons for you and break them down below so you can decide how to use coffee grounds in the garden.

Benefits of coffee grounds to plants

Should you use coffee grounds as mulch?

Using mulch in your garden can be beneficial, but many people find the cost of mulch too expensive to turn into organic matter. Straw and compost can be used as mulch, but not many people have tons of straw lying around, and compost takes months to create. So it seems as though coffee grounds would be the perfect solution for gardeners in need of mulch.

However, coffee grounds can actually harm the roots of seedlings by inhibiting growth if applied too thick. Also, coffee contains caffeine, which has been found to suppress the growth of plants. Coffee grounds are tiny particles that are prone to locking together and forming clumps. These clumps can become a barrier to water and other nutrients that the plants need to absorb.

So what is the answer regarding using coffee grounds as mulch? The solution is to mix coffee grounds with other organic matter such as leaf mold or compost before using it as mulch. You can also rake coffee grounds into the top layer of soil so they can’t clump together. The key is to have variable particle sizes in your soil and mulch to promote good soil structure, allowing water and nutrients to be absorbed properly.

Benefits of coffee grounds to plants

Can coffee grounds be used as a fertilizer?

Coffee grounds contain several essential nutrients, such as nitrogen, potassium, and phosphorus, along with several micronutrients — all of which make using coffee grounds for plant fertilizer a great idea. The amount of nutrients in each batch of coffee grounds varies, but ultimately, coffee grounds can be used as a slow-release fertilizer. (Coffee grounds aren’t as acidic as some claim, so you don’t have to worry about that.)

Sprinkle coffee grounds in a thin layer onto your soil to use as a fertilizer. Just make sure you don’t use too much or pile it too closely; just like you have to be careful when using coffee grounds as mulch, you don’t want the particles to clump and create a water-resistant barrier.

Another plus? Worms like coffee grounds and worms are a necessary part of the ecosystem that is any garden. By adding coffee grounds, you’ll be making your green space a little more inviting to worms.

Benefits of coffee grounds to plants

Should I add coffee grounds to my compost?

Composting can be very beneficial. There are two types of compost material: green and brown. Coffee grounds fall into the green category since they are a green material, which means they are rich in nitrogen. (Coffee grounds typically have about 1.45% nitrogen.) Other green materials are food scraps and grass clippings. All of these green materials contain magnesium, calcium, potassium, and other trace minerals.

You can throw your coffee grounds (paper filter and all) into your green compost bin, but when it comes time to put the compost in the garden, you must mix your green compost with some brown compost. Too much green material and your compost will smell, but not enough will defeat the purpose, too: The compost won’t heat up the way it needs to. Brown compost material consists of items such as newspapers and dried leaves. The general rule is to have a 4-to-1 brown to green compost material ratio.

Benefits of coffee grounds to plants

Do coffee grounds work as a pesticide?

Many people also swear that used coffee grounds in garden beds will eliminate the slugs and snails damaging their plants. Though the reason is not apparent — whether it is the texture of the coffee grounds or caffeine content, the slimy creatures tend to avoid the stuff at all costs. The same has been thought for ants, but there isn’t any science to back this up. The only way to find out if your garden will benefit from coffee grounds as a natural pesticide is to try it and see if it acts as a barrier to pesky insects. However, you should prepare a backup plan to exterminate the plants’ threats if the coffee grounds don’t work.

Coffee grounds can be a great addition to any garden if you follow the guidelines we’ve outlined above. Used coffee grounds could be the answer if you’re an avid gardener and feel like something has been missing. Whether you need mulch, fertilizer, compost, or pesticide, used coffee grounds could be the mystery ingredient you didn’t even know you needed to take your garden to the next level. And now that you know the facts, you can participate in that heated debate about coffee grounds at the next garden club meeting.

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— Update: 31-12-2022 — cohaitungchi.com found an additional article Coffee Grounds for Gardening – Pros, Cons, and How to Use Them from the website www.trees.com for the keyword benefits of coffee grounds to plants.

Coffee grounds are often used to remove odors, prevent insects & pests, and scrub the body. But did you know that gardeners also use the waste of the coffee to fertilize the garden, improve the soil quality, and so on?

But some don’t recommend them for gardening for some downsides of coffee grounds. So keep reading to learn into details about the coffee grounds and how to use them properly in the garden.

What are Coffee Grounds, and How Can They be Used in Gardening?

Coffee grounds are the waste that results from preparing or brewing coffee. Many coffee shops have huge amounts of coffee grounds going in the waste, which they will often happily give to customers for free to be used in their gardens.

Gardeners can use coffee grounds in a range of ways in the garden. They can be successfully used to improve soil quality, fertilize plants, and deter pests. However, there are some drawbacks to using coffee grounds in the garden, and some instances where they should be avoided. To learn how you can make use of this organic material that would otherwise be wasted, read on.

Pros and Cons of Using Coffee Grounds for Plants


Improves Soil Drainage

Used coffee grounds are a free organic material, and so if you want to amend your soil to help improve soil quality, then adding in a few cups of grounds every now and again can be a good way to do this. By increasing the amount of organic material in your soil, drainage will be improved, which helps to ensure that water does not sit around the roots of plants and cause rotting.

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Every gardener knows that good drainage is essential for the health of most plants, so there’s no reason not to use your coffee grounds for this purpose when they might otherwise end up in the garbage. The one rule with adding coffee grounds to improve drainage is to make sure you mix it in well with the soil. Coffee grounds are made from very small particles that can become compacted if they are not mixed well with other materials, which will actually create barriers similar to a clay type soil that is the exact opposite of what you are trying to achieve.

Helps to aerate the soil

Similar to how adding coffee grounds to the soil will improve drainage, it will also help to aerate the soil. This is because amending the soil with any organic matter will help to improve aeration, thereby allowing roots to better absorb moisture and nutrients, and helping with the overall health of the plant.

Improves Soil Water Retention

Amending your soil with coffee grounds will also improve water retention, as it is a type of organic matter that will improve the overall health of the soil, including its ability to retain water. This will especially help plants that like to grow in moist soil, as after rain or watering, the soil will remain moist for longer. A soil that retains water well will also need to be watered less frequently, which can reduce water bills and conserve energy.

Adds Nitrogen to Compost

Coffee grounds can be added to compost as green waste (despite the fact that it is brown in color!) Coffee grounds contain reasonable levels of nitrogen, which will break down and create a compost that is high in essential nutrients. Nitrogen helps to encourage lush leafy growth, so using a compost containing coffee grounds amongst your plants will promote foliage health.

Can Deter Slugs and Snails from Plants

Many people claim that used coffee grounds act as a deterrent against slugs and snails. These nasty pests are a common problem for gardeners, as they feed on foliage that can look unsightly and, in some cases, even cause the decline and deterioration of plants. It is thought that the smell and taste of the coffee grounds deter these pests, and also that the grainy texture can act as a physical barrier that slugs and snails do not want to cross.

Can Act as a Cat Repellant

If you have a problem with cats spraying or pooping in your garden, you’re not alone. Cats commonly use gardens as litter trays, as they seem to enjoy defecating on soil, mulch, and gravel. This can be a very unpleasant problem that many gardeners battle with, and it is incredibly frustrating to find the garden you have spent time nurturing to be overrun with cat feces. It’s a very serious problem if you have children, as cat droppings and urine contain elements that can be very harmful if touched or ingested by humans, and it can even cause blindness.

To try to combat a cat problem, pour your coffee grounds in small piles around your plants, or mix it into the top layer of your soil. The small is believed to deter cats, though it may need to be used in conjunction with other preventative methods if you have a severe cat problem. Ensure you don’t create a carpet of coffee grounds, as this can block the soil from getting moisture.

Promotes Good Worm Population

Coffee grounds are reportedly a popular choice of food for worms, so using them in your soil or in your compost can increase the worm population. A good worm population in your garden is vital for plant root health, and also in the breaking down of compost. Vermicomposters report that their worms love to feast on coffee grounds, so adding this green material routinely to your compost will keep the worms happy and working away.

Can be Used as a Mulch

Benefits of coffee grounds to plants

Coffee grounds can be mixed with other organic materials, such as shredded leaves, and used as mulch. When layered over the top of the soil around plants, this can help to prevent moisture from evaporating from the soil, as well as helping the soil to retain heat in the winter and keep cool in the summer.

Mulching over your soil can also inhibit weed growth. Weed seeds will not be able to access soil as easily as the mulch acts as a physical barrier, and it also prevents light from getting through to the soil, which will prevent many types of weeds from germinating. If you do want to use coffee grounds as mulch, you should always mix it with another organic material because if used alone, the small particles can become compacted and prevent water from getting through to the soil.

Works as a Slow Release Fertilizer

Benefits of coffee grounds to plants

Amending your soil with coffee grounds will introduce slow-release nutrients, thereby making it an effective fertilizer. Used coffee grounds contain a good amount of nitrogen,  low levels of phosphorus and potassium, and some other micronutrients. These are all nutrients that are essential to plant health, so introducing them to your soil will be beneficial. They won’t be immediately available to the plant’s roots and will be released slowly during the breakdown cycle of the grounds, making them great as a gradual fertilizer.

Reduces Waste and Reduces Chemical Use

Coffee grounds are a waste item, which, if not put to good use, will typically end up in the garbage can, and ultimately in a landfill. Recycling or reusing any item is a great way to make a positive impact on the earth and on the environment. Coffee grounds are an organic material that, when reused, can be considered as an eco-friendly choice.

If you use coffee grounds as a fertilizer instead of a synthetic fertilizer, you will also be reducing the number of chemicals being put into the earth and contributing to a more organic and natural landscape while protecting local waterways and the delicate balance of the ecosystem.


Can Form Dense Barrier over Soil

Coffee grounds are composed of very small particles that can easily become compacted together when they dry out, forming a solid barrier. If you use neat coffee grounds, for example, as a mulch or top dressing, then you will be creating something with a texture similar to clay soil, which is obviously bad news for plants. A physical barrier over the top of your soil that is impenetrable by water will result in your plants dying from thirst.

May Be Harmful to Dogs in Large Quantities

If you have a canine friend who curiously tastes anything that takes his interest, then you might want to avoid laying coffee grounds around your plants. If ingested, coffee grounds can be toxic to dogs. A fairly large quantity would need to be consumed to result in fatalities, but even so, it is probably not worth the risk of harming your pet.

Inhibits Seedlings from Growing

Caffeine can inhibit seedlings from growing, and in fact, this is one of the components of coffee plants-that they grow well because the caffeine they contain prevents nearby competition from thriving. Therefore, if you are growing seeds or young plants, you should avoid having coffee grounds anywhere near them. They can destroy their roots and lead to the quick demise of the plant before it has even had a chance.

Caffeine Can Suppress Root Growth

Just like how caffeine can inhibit seedlings from becoming established, caffeine can also have negative effects on mature plants. It can restrict root growth and cause the plant to become stunted. Coffee grounds are less likely to be harmful to mature plants compared to seedlings, but it is still worth considering if you don’t want to risk the health of a plant you are particularly fond of.

Antibacterial Properties can Destroy Good Bacteria in Soil

Coffee has antibacterial properties. While in general life, this is considered to be an advantage, when it comes to soil health, this can actually cause big problems. There are many different types of good bacteria living in soil, which keep pests and disease in check. By introducing a material that is antibacterial, you will kill all of the good bacteria that will make the soil vulnerable to pests and disease in the future. The destruction of good bacteria will also alter the natural biodiversity of the soil, which can cause all sorts of problems for earthworms and other creatures residing in your soil.

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May Kill Off Earthworms in Compost

Some composters attest to their worms loving coffee grounds to feast on, but this is a contested issue as some studies show that using coffee grounds in compost can actually kill off earthworms and reduce the overall worm population in compost. Worms are vital in breaking down compost and helping it to decompose, so diminishing the worm population would certainly be a bad thing to do. More research needs to be done on this topic to find a definitive conclusion.

Used Coffee Grounds are Not Acidic

Many people recommend using coffee grounds on the soil to help bring down the pH of alkaline soil to a more neutral because coffee is acidic. Some people also suggest using it in the soil around acidic-loving plants, such as blueberries, hydrangeas, and azaleas. However, while fresh coffee grounds are acidic, used coffee grounds are not. This will differ slightly between brand and coffee type, but the vast majority of used coffee grounds will have a neutral pH, so they are useless for amending soil pH.

Using fresh coffee grounds on the soil will also not help because the acid in coffee is water-soluble, so as soon as it rains, any acidic content held in the grounds will be washed away. Using any type of coffee grounds in the soil as an attempt to alter its pH is a waste of time and a waste of good coffee!

How to Use Coffee Grounds for Plants

If you make filtered coffee at home, then you likely have plenty of coffee grounds going to waste each day. Use a large tub or a bucket in your kitchen to empty your grounds into, and at the end of each week, you can use it to benefit your garden. Note that if you make instant coffee, then you won’t have any grounds leftover, which is a great reason to move over to filtered coffee (plus the great taste!), or you could ask a neighbor or local coffee shop for their used grounds.

To use coffee grounds in your garden, always mix them well, whether that be mixing them in with your existing soil or with another organic matter such as lawn clippings or shredded leaves to make a mulch.

— Update: 31-12-2022 — cohaitungchi.com found an additional article Composting With Coffee Grounds – Used Coffee Grounds For Gardening from the website www.gardeningknowhow.com for the keyword benefits of coffee grounds to plants.

Whether you make your cup of coffee daily or you have noticed your local coffee house has started to put out bags of used coffee, you may be wondering about composting with coffee grounds. Are coffee grounds as fertilizer a good idea? How do coffee grounds used for gardens help or hurt? Keep reading to learn more about coffee grounds and gardening.

Composting Coffee Grounds

Composting with coffee is a great way to make use of something that would otherwise end up taking up space in a landfill. Composting coffee grounds helps to add nitrogen to your compost pile.

Composting coffee grounds is as easy as throwing the used coffee grounds onto your compost pile. Used coffee filters can be composted as well.

If you will be adding used coffee grounds to your compost pile, keep in mind that they are considered green compost material and will need to be balanced with the addition of some brown compost material.

Coffee Grounds as Fertilizer

Used coffee grounds for gardening does not end with compost. Many people choose to place coffee grounds straight onto the soil and use it as a fertilizer. The thing to keep in mind is while coffee grounds add nitrogen to your compost, they will not immediately add nitrogen to your soil.

The benefit of using coffee grounds as a fertilizer is that it adds organic material to the soil, which improves drainage, water retention, and aeration in the soil. The used coffee grounds will also help microorganisms beneficial to plant growth thrive as well as attract earthworms.

Many people feel that coffee grounds lower the pH (or raise the acid level) of soil, which is good for acid loving plants. This is only true for unwashed coffee grounds though. Fresh coffee grounds are acidic. Used coffee grounds are neutral. If you rinse your used coffee grounds, they will have a near neutral pH of 6.5 and will not affect the acid levels of the soil.

To use coffee grounds as fertilizer, work the coffee grounds into the soil around your plants. Leftover diluted coffee works well like this too.

Other Uses for Used Coffee Grounds in Gardens

Coffee grounds can also be used in your garden for other things.

  • Many gardeners like to use used coffee grounds as a mulch for their plants.
  • Other uses for coffee grounds include using it to keep slugs and snails away from plants. The theory is that the caffeine in the coffee grounds negatively affects these pests and so they avoid soil where the coffee grounds are found.
  • Some people also claim that coffee grounds on the soil is a cat repellent and will keep cats from using your flower and veggie beds as a litter box.
  • You can use coffee grounds as worm food too if you do vermicomposting with a worm bin. Worms are very fond of coffee grounds.

Using Fresh Coffee Grounds

We get lots of questions about using fresh coffee grounds in the garden. While it’s not always recommended, it shouldn’t be a problem in some situations.

  • For instance, you can sprinkle fresh coffee grounds around acid-loving plants like azaleas, hydrangeas, blueberries, and lilies. Many vegetables like slightly acidic soil, but tomatoes typically don’t respond well to the addition of coffee grounds. Root crops, like radishes and carrots, on the other hand, respond favorably — especially when mixed with the soil at planting time.
  • The use of fresh coffee grounds are thought to suppress weeds too, having some allelopathic properties, of which adversely affects tomato plants. Another reason why it should be used with care. That being said, some fungal pathogens may be suppressed as well.
  • Sprinkling dry, fresh grounds around plants (and on top of soil) helps deter some pests same as with used coffee grounds. While it doesn’t fully eliminate them, it does seem to help with keeping cats, rabbits, and slugs at bay, minimizing their damage in the garden. As previously mentioned, this is thought to be due to the caffeine content.
  • In lieu of the caffeine found in fresh, unbrewed coffee grounds, which can have an adverse effect on plants, you may want to used decaffeinated coffee or only apply fresh grounds minimally to avoid any issues.

Coffee grounds and gardening go together naturally. Whether you are composting with coffee grounds or using used coffee grounds around the yard, you will find that coffee can give your garden as much of a pick me up as it does for you.

— Update: 01-01-2023 — cohaitungchi.com found an additional article How to Use Coffee Grounds in Your Garden from the website www.thespruce.com for the keyword benefits of coffee grounds to plants.

If you make a daily pot of coffee, you have a fabulous source of organic matter right at your fingertips. Coffee grounds can make your garden happier in several ways, and not just that coffee gives you more energy for weeding and pruning. Don’t toss the grounds! You can put them to work.

Coffee in Compost

Put coffee grounds in your compost bin. There are two types of compost material: brown and green. Your coffee grounds may be brown in color, but in compost jargon they are green material, meaning an item that is rich in nitrogen. Coffee grounds are approximately 1.45 percent nitrogen. They also contain magnesium, calcium, potassium, and other trace minerals. Other green compost materials include food scraps and grass clippings.

Adding coffee grounds and used paper coffee filters to your compost will provide green compost material. However, it must be balanced with brown compost material, which includes dry leaves and newspapers. There should be a 4-to-1 ratio of brown compost material to green compost material. If you have too much green material your compost pile will start to smell. If you don’t have enough, the compost pile won’t heat up.

Read more  Coffee Grounds for Gardening – Pros, Cons, and How to Use Them

The Spruce / Sarah Crowley

Fertilize With Coffee Grounds

Add coffee grounds directly to the soil in your garden. You can scratch it into the top couple inches of soil, or just sprinkle the grounds on top and leave it alone. In smaller amounts, especially when mixed with dry materials, coffee grounds will give up their nitrogen. Used coffee grounds are actually nearly neutral in pH, so they shouldn’t cause concerns about their acidity. Be careful not to use too many coffee grounds or pile them up. The small particles can lock together, creating a water resistant barrier in your garden.

You can also make coffee ground “tea.” Add 2 cups of used coffee grounds to a 5-gallon bucket of water. Let the “tea” steep for a few hours or overnight. You can use this concoction as a liquid fertilizer for garden and container plants. It also makes a great foliar feed you can spray directly on the leaves and stems of your plants.

The Spruce / Sarah Crowley 

Feed Your Worms

Add coffee grounds to your worm bin every week or so. Worms love coffee grounds! Just don't add too many at once, because the acidity could bother your worms. A cup or so of grounds per week for a small worm bin is perfect. In addition to using coffee grounds in your worm bin, earthworms in your soil will also be more attracted to your garden when you use them mixed with the soil as fertilizer.

Keep the Pests Away

Create a slug and snail barrier. Coffee grounds are abrasive, so a barrier of grounds placed near slug-prone plants may just save them from these garden pests. However, be warned that some researchers quibble with this advice and don’t think it is effective. You may want to have a backup plan in mind if it doesn’t work. Many cats dislike the smell of coffee grounds and may avoid using your garden as a litter box if you mix coffee grounds into the soil.

The Spruce / Sarah Crowley 

Fresh Coffee Grounds for Acid-Loving Plants

While used coffee grounds are only slightly acidic, fresh (unbrewed) coffee grounds have more acid. Your acid-loving plants like hydrangeas, rhododendrons, azaleas, lily of the valley, blueberries, carrots, and radishes can get a boost from fresh grounds. However, tomatoes do not like fresh coffee grounds; keep them out of that area of the garden. This could be a good use for coffee that is getting old in your pantry or a type you bought for visiting friends but isn’t your usual cup of joe.

Fresh coffee grounds still have most of their caffeine content as well as the acid. Don't use coffee grounds on seedlings or very young plants, as caffeine can stunt their growth. Be cautious in using fresh grounds around pets or your wire terrier may become extremely wired.

The Spruce / Sarah Crowley

Dissenting Research Into Coffee Grounds in the Garden

One 2016 research study found that using spent coffee grounds in growing broccoli, leek, radish, viola, and sunflower resulted in poorer growth in all soil types, with or without additional fertilizer. The good news is that the coffee grounds improved the water holding capacity of the soil and decreased weed growth. The researchers think the poorer growth was due to the plant-toxic compounds naturally present in the coffee grounds. If you aren't getting the results you hoped for with coffee grounds, you may want to try your own experiments with and without them in your garden.

— Update: 04-01-2023 — cohaitungchi.com found an additional article A Common-Sense Guide to Using Coffee Grounds in the Garden from the website www.growveg.com for the keyword benefits of coffee grounds to plants.

Coffee shops often give coffee grounds away free to gardeners, as they’re a waste product they would normally have to pay to dispose of. For coffee-loving gardeners like me, this freely available resource sounds like a real boon. But some gardeners suggest that using coffee grounds could be ineffective or, worse, harmful to plants.

I decided to sort the facts from the hype and find out just how beneficial – or otherwise – coffee grounds are in the garden.

Using Coffee Grounds as Mulch

Mulching is incredibly beneficial but it’s notoriously difficult to come by compost, straw or other organic matter in large enough quantities at a low enough price. Using free coffee grounds seems like the perfect solution, but some gardeners have found that using coffee grounds directly on the soil has had a disastrous effect on plants. However this seems to be linked to using thick blankets of it to mulch around plants and over seeds.

With care, used coffee grounds can be added to the vegetable garden soil

The reason for this could be that coffee beans contain caffeine, which is said to suppress the growth of other plants to reduce competition for space, nutrients, water and sunlight. How much caffeine actually remains in used coffee grounds is debatable, and some plants will be more sensitive to caffeine than others. It would be sensible to avoid spreading coffee grounds around seeds or seedlings as they may inhibit germination and growth.

There is a more obvious reason why using coffee grounds alone for mulching could be detrimental. Like clay soil, coffee grounds consist of very fine particles that are prone to locking together. This turns them into a barrier that will resist water penetration and eventually result in plants dying of thirst.

The solution is to mix coffee grounds with other organic matter such as compost or leafmold before using it as a mulch. Alternatively, rake your coffee grounds into the top layer of soil so that they can’t clump together. Variable particle sizes is key to good soil structure.

Coffee grounds are often said to be acidic but this can vary a lot, from very acidic to slightly alkaline, so don’t expect them to acidify higher pH soils.

Sprinkle used coffee grounds around plants as a slow-release fertiliser

Using Coffee Grounds as Fertilizer

Many of us will have dumped the cold remains of a forgotten coffee in a plant pot at some point, and then perhaps wondered if it was the wrong thing to do! But it turns out that coffee grounds contain a good amount of the essential nutrient nitrogen as well as some potassium and phosphorus, plus other micronutrients. The quantity and proportions of these nutrients varies, but coffee grounds can be used as a slow-release fertilizer.

To use coffee grounds as a fertilizer sprinkle them thinly onto your soil, or add them to your compost heap. Despite their color, for the purposes of composting they’re a ‘green’, or nitrogen-rich organic material. Make sure to balance them with enough ‘browns’ – carbon-rich materials such as dried leaves, woody prunings or newspaper. Your compost heap’s tiny munchers and gnawers will process and mix them effectively, so using coffee grounds in this way is widely accepted to be safe and beneficial.

Many vermicomposters say that their worms love coffee grounds, so small quantities could also regularly be added to a worm bin if you have one. Paper coffee filters can go in too.

Used coffee grounds can safely be added to the compost heap

Coffee Grounds as a Natural Pesticide

An oft-repeated nugget of advice is to spread used coffee grounds around plants that are vulnerable to slug damage. There are two theories why: either the texture of the grounds is abrasive, and soft-bodied slugs prefer not to cross them, or the caffeine is harmful to slugs so they tend to avoid it.

However in an experiment slugs took just seconds to decide to cross a barrier of coffee grounds! The same researcher also sought to find out if coffee grounds would repel ants, with similar results – ants may not particularly like coffee grounds, but they won’t scarper out of your garden to get away from them.

Enjoy your daily brew and recycle used coffee grounds in the garden

Coffee Grounds and Dogs

One word of warning though: coffee grounds may not have much effect on pests, but they can be harmful to pets in large enough doses. It’s hard to say what would be a large enough dose to cause poisoning because the amount of caffeine in used coffee grounds varies. But if you have a dog that insists on sampling anything that smells halfway agreeable, it would be wise to avoid laying coffee grounds directly onto the garden. Bury them in your compost heap instead.

Coffee grounds are free organic matter, whether a by-product of your at-home daily brew or collected from coffee shops that are only too glad to give them away for nothing. If used with care and common sense, they are a worthwhile addition your compost heap and your soil.

Have you used coffee grounds in the garden? What was your experience? Share it with us by leaving a comment below!


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About the Author: Tung Chi