Should you compost your used coffee grounds?

10 Aug 2022


Give your garden a new lease of life by composting your used coffee grounds

Want your morning coffee to go further? Whether you’re green-fingered or simply can’t go without a caffeinated drink, here’s how to make the most of your used coffee grounds. Let’s explore how coffee grounds can enrich compost.

Kitchen compost bin beside vegetable peelings

Should you compost used coffee grounds?

Sustainability is an issue at the forefront of everyone’s minds right now. Many of us are constantly looking for new and innovative ways to reuse, recycle and reduce waste to protect our planet. It’s crucial to use natural resources and ingredients efficiently to reduce waste and consumption. But have you considered reusing or composting used coffee grounds before?

There’s no denying that many of us enjoy a caffeine boost throughout the day. From creamy lattes to strong espressos, we adore vibrant coffee beverages. However you take your coffee, you’re most likely left with used coffee grounds from your brew of choice.

It can be tempting to bin your coffee grounds. Some people even wash them down the sink – but did you know this can cause major drain issues? You may want to consider disposing of your used coffee grounds in a more environmentally-friendly manner. One way to do so is by composting them.

Coffee grounds in compost

It’s always good to have a varied blend of organic matter on your compost heap. From vegetable trimmings to black and white newspaper, each organic matter releases nutrients and breaks down, producing rich compost that plants love.

Coffee makes incredible, nutrient-rich compost due to its natural components.

Coffee grounds in compost count as ‘green matter’. They release micro-nutrients, such as nitrogen. It’s important to note that, when adding coffee grounds to your compost, you should try to balance the green matter with brown compost material, too. Brown compost includes dry, fibrous plant waste such as garden cuttings and trimmings. These are more resistant to decay and considered ‘slow-burning’ matter for your compost heap.

Because used coffee grounds are close to a neutral pH, they’re a great soil addition. Most of the acid in coffee is water-soluble. As such, it’s released into the freshly-brewed coffee and not present in the leftover grounds.

Coffee grounds can also improve the soil ’tilth’ or structure. Coffee is also commonly remarked as being a natural slug and snail repellent in the garden. And most importantly of all, composting coffee grounds reduces the level of organic matter in landfill.

Coffee grounds

Is it possible to put too much ground coffee in your compost bin?

As coffee is such a superb, natural addition to compost, the grounds can be used liberally on your at-home compost heap. However, it’s always important to bear in mind the balancing act between green matter and brown matter, to ensure an even mix of nutrient-rich compost and also for the speediest decay time.

As most of us enjoy at least one cup of coffee a day, green matter such as vegetable peelings, fruit cores and coffee grounds can sometimes overload compost heaps. Look out for these telltale signs that your compost heap is off-balance. It might be time to add some organic brown matter such as shredded paper or dried leaves:

  • Overheating. Too much fresh kitchen waste and green matter can cause your compost to overheat. This can be detrimental as it kills off beneficial microbes and microorganisms. Try mixing more dry ‘brown’ materials and combining really well to avoid this from happening.
  • Bad smells. If you notice your compost bin smelling foul (sometimes like rotten eggs!) when turning it, it’s a sign that you’re low on brown materials.
  • Ammonia aroma. Too many coffee grounds (or other high-nitrogen materials) can cause your pile to release odorous ammonia gases. To eliminate these smells and improve the balance of your compost, add more dry materials into the mix.
  • Unappealing texture. If your compost looks too wet, shiny or slimy, it’s an indication that there may not be enough carbon materials present to offset the nitrogen matter. Simply top up with garden waste and brown matter and mix well to restore harmony in your compost pile.

Which plants can coffee compost help most?

Many green-fingered coffee-lovers choose to add used coffee grounds straight onto the soil as an active fertiliser. This can help improve drainage, water retention, and even aeration throughout the soil. Used coffee grounds can also help microorganisms, which are crucial to plant growth and attract beneficial earthworms too.

Plants that thrive most from coffee compost are acid-loving azaleas, lilies, and hollies. The coffee grounds help to lower the pH level of the soil.

Other coffee-loving plants include hydrangeas, which will see a colourful burst from coffee compost. Roses love a high-nitrogen content companion to take pH levels from neutral to acidic. You can also use your coffee compost to encourage grass growth and vibrancy. Why not try it on your indoor plants, and as the base for mulch around flowers and vegetables?

Many other plants also benefit from coffee compost too. However, make sure you mix the compost in well rather than placing it on top to prevent hardening and allow water to enter the ground.

While used coffee ground compost is hugely beneficial across the garden, there are some exceptions to the rule. Steer clear from using coffee compost with tomatoes and rhododendrons. It may cause leaf tips to turn brown. It’s also a good idea to keep coffee grounds away from freshly seeded areas, as they can reduce germination.

Learn more about using coffee grounds as fertiliser. Read more here.

Garden vegetable patch with lettuce

Enjoy delicious coffee that’s also great for the garden

At Hotel Chocolat, one of our key principles is sustainability. Since moving into the vibrant world of high-quality and responsibility-sourced coffee, we are committed to remaining eco-driven and environmentally friendly. Our ethical ingredients are at the heart of all of our products, including our Rabot Estate Coffee.

Why not try our Podster Coffee System? Barista-grade coffee, from sustainable pods, at home.

And for creating your own at-home used coffee grounds compost, pair it with our Podcycler. This is our innovative answer to sustainable coffee pod waste. From bean to cup, we strive to produce satisfying coffee that treads lightly on the planet, always.