Coffee Grounds For The Garden

You can generally get free coffee grounds from your local coffee shop. For example, a typical Australian café produces about 80 kg of coffee grounds each week. This is often ending up in landfills, so you are helping them get rid of a waste product they usually need to pay to get rid of.. So they’re keen to help you and help themselves. But the question remains…

Are Coffee Grounds Good For The Garden

Indeed, coffee grounds are great for the garden – with a few caveats to bear in mind. If you are fond of gardening, coffee grounds are not a waste product. They are a useful product you are delighted to get your hands on. Coffee grounds are rich in potassium, nitrogen, and carbon, so they can really feed your garden’s soil.

Some gardeners will tell you that using coffee grounds in the garden is either useless or even damaging. Much of this negative to neutral opinion comes from failure to adhere to a few key principles of proper coffee grounds use in the garden. As with anything, it is the details that matter. Let’s go through the main issues and decide if they are indeed worth it.

Are Coffee Grounds Good For Compost

Used coffee grounds are too acidic to be used alone as a compost. They need to be incorporated with other forms of organic matter, such as sawdust, straw, leaf mold, or other fibrous material. A 50/50 mixture of coffee grounds and sawdust proves particularly useful. It’s best to keep away from the sawdust from treated timbers and make sure it rots completely so that the sawdust won’t rob the soil of nitrogen like when it is ‘too green’.

Are Coffee Grounds A Good Mulching Material

There’s no doubt about the usefulness of mulching, and coffee grounds can play an important role in it. Because it can be difficult to get large quantities and cheap prices for compost, straw, and other raw materials, coffee grounds are a great addition to the whole process.

However , if you mix the grounds in with some fibrous material before spreading it on the soil, your garden will produce healthier plants than if you just spread it on the soil.

Some claim the negative repercussions of using straight coffee grounds as mulch result from the  plants absorbing the residual caffeine in the grounds. Although it is true in some cases for some species of plants with unusually strong coffee, it is probably due to too much acidity causing stress on the plants.

So mix it with other mulching materials, and don’t put it on too thick, both to prevent it from becoming too acidic and also to ensure the ground doesn’t become an impenetrable layer that doesn’t let the moisture through to the soil below.

Make sure to scatter the coffee grounds on top of the layers of soil, so as to keep them from clumping together. If not, mix coffee grounds with various other ingredients like compost or leaf mold before spreading the mixed mulch on the garden.

Coffee Grounds As Fertilizer

They make an excellent natural slow-release fertilizer. Just sprinkle small amounts of the grounds around plants to allow the nutrients to release slowly.

Used ground coffee has many useful components. It is rich in nitrogen, an important nutrient for gardens. They also contain potassium and phosphorus as well as other micronutrients. The quantities and ratios of these nutrients may fluctuate, but this doesn’t matter as long as you spread it around as a slow-release fertilizer – unless you overdo it. Your plants will take up nutrients as they need them.

Can You Feed Coffee Grounds To Worms?

Many keen gardeners say that their worms like coffee grounds, so small amounts of it can be added to your worm farm on a regular basis. If you don’t have a worm farm, you should get one because what they produce for your garden is just marvelous. You can also add coffee filters for the delightful little critters to munch through and turn into wonderful worm castings. However, there are some guidelines to follow in the process:

  • It is essential to combine all food scraps including coffee grounds and give it all a good stir so the grounds are even throughout the mix. For example, if you are adding fruit and veggie scraps, fruit rinds, etc, mix in the day’s coffee grounds.
  • If you have not fed your worms for some time, it is best not to give them coffee grounds as the break of their fast. Coffee grounds are too rich a source of nitrogen to feed to the worms as a stand-alone food. Too much of a good thing and all that. 

Coffee Grounds: A Natural Deterrent For Snails And Slugs?

One piece of oft-repeated advice is to scatter dried ground coffee around plants likely to be eaten by snails and slugs. Others say doing this is a complete waste of time and is not worth the trouble. For those who believe, there appear to be two different theories:

  • The rough texture of the coffee grounds clings to the soft-bodied slugs and snails as they try to traverse across it, causing them to avoid it.
  • The used coffee grounds have high enough levels of caffeine remaining, thereby acting as a snail and slug deterrent.

Coffee Grounds and Dogs

Coffee grounds can be toxic to dogs if they eat large amounts of it. So if you have one of those doggies who just scoff any object it finds in the yard, you need to make sure to work the coffee grounds into the soil or other mulch so that the little darling doesn’t  inadvertently poison itself. Alternatively, just compost it in the compost heap instead. The good side is that it would take a very large amount of the grounds to make a dog sick, but as they say, it’s better to be safe than sorry.


I’ve been around farming all of my life. Farmers Life Blog is a way I can share my passion for all things farming and gardening and hopefully share some of my knowledge and experience through the process. Shootin' the breeze doesn't have to be confined to the front porch anymore, now there's a whole world to share my deep and abiding love with.

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