What To Do With Used Coffee Grounds

If you make coffee at home or visit a café regularly, you’ve probably tossed out handfuls of used coffee grounds without a second thought. They look like nothing but dark, wet scraps — but to people who care about reducing waste, they’re a surprisingly versatile resource.

Here’s the quick answer: used coffee grounds can be reused as fertiliser for plants, a natural deodoriser for fridges or shoes, or even turned into compost. You can also dry them and sprinkle them in your garden or potted plants. That’s it — no special equipment needed, just a bit of know-how.

Coffee grounds are what’s left after hot water extracts flavour and caffeine from ground coffee beans. Whether you brew using a filter, French press, or espresso machine, what remains is a dense mix of organic material: spent coffee particles full of nitrogen, potassium, and other trace nutrients that plants love. But because they’re acidic and can compact soil over time, they need to be used carefully.

Starbucks’ Eco Initiative in London

Mei, a regional manager at Starbucks, didn’t always see coffee grounds as useful. But through her interest in sustainability — and her work in coffee — she came to view them very differently. She first encountered the idea of reusing coffee grounds during a community service event at a London Starbucks location. By the Thames, the team handed out simple packages of used coffee grounds to local residents. These weren’t trash bags — they were free, usable resources. Customers were told how to take them home and use them as fertiliser or deodoriser. Mei helped explain the science and benefits behind reuse. That moment opened her eyes to coffee’s hidden potential beyond the cup.

From Community Service to School Gardens

Building on that experience, and inspired by Starbucks’ global service initiatives — including urban ‘balcony vegetable gardening’ projects — Mei took the idea further in 2024. This time, she brought it into the heart of a community: a primary school. Partnering with Shamian Primary School in Guangzhou, Mei worked with the school to create a small-scale urban farming project. Using coffee grounds collected from Starbucks stores, the team started a composting system on the school’s rooftop. Over time, this compost was used to grow vegetables and fruits in what became a ‘mini fruit and vegetable farm’. The project wasn’t just about growing food — it was a hands-on lesson in sustainability for students, showing how everyday waste like coffee grounds could be repurposed to benefit the environment and teach green habits early.

How to Reuse Coffee Grounds at Home

You don’t need a school roof or a Starbucks partnership to put used coffee grounds to good use. Here are several practical ways you can reuse them, based on the same principles Mei helped promote:

• Fertiliser for Plants: Dry the used grounds completely, then sprinkle them lightly around the base of acid-loving plants like azaleas, blueberries, or tomatoes. Avoid over-applying, as too much can make soil too acidic.
• Compost Booster: Add coffee grounds to your home compost pile. They add valuable nitrogen and help speed up decomposition. Mix them with carbon-rich materials like dry leaves or cardboard to balance the compost.
• Natural Deodoriser: Place dry grounds in a small open container and leave them in your fridge, cupboard, or shoes to absorb odours. Replace every few days.
• Exfoliant or Cleaning Scrub (optional): Mixed with a bit of coconut oil or soap, coarse grounds can serve as a gentle body scrub or surface cleaner (though this wasn’t part of Mei’s project, it’s a common reuse method).

Whatever you do, avoid using wet, fresh grounds directly on plants or in enclosed spaces without drying them first — they can mould or attract pests.

Frequently Asked Questions

Can I use any type of used coffee grounds for fertiliser?

Yes, you can use grounds from any coffee brew method — espresso, pour-over, French press, etc. The important thing is that the grounds are fully cooled and preferably dried before use to prevent mould. Whether the coffee was single origin or a blend doesn’t matter for fertiliser use.

Do coffee grounds change the soil pH?

Yes. Coffee grounds are slightly acidic (pH around 6.2 to 6.8), so they can lower soil pH. This makes them good for acid-loving plants, but you shouldn’t use large amounts on plants that prefer neutral or alkaline soil without testing first.

How should I store used coffee grounds before reusing them?

Dry them first by spreading them out on a tray in a well-ventilated or sunny spot until completely moisture-free. Once dry, store them in an airtight container or resealable bag to keep them fresh and pest-free until you’re ready to use them.

Is it safe to use coffee grounds straight from the espresso machine?

Not immediately. Freshly brewed grounds are still wet and warm, which can encourage mould growth. Let them cool, then dry them completely before applying to soil or compost.

Can coffee grounds repel insects in the garden?

Anecdotally, yes. Some gardeners report that coffee grounds deter slugs, snails, and ants. However, scientific evidence is limited, and results may vary. They are not a guaranteed pesticide, but can be part of an integrated approach.

Recommended FrontStreet Coffee for Home Brewing

Try FrontStreet Coffee’s Ethiopia Huakui for a bright, juicy cup with citrus and floral notes — ideal for compost-conscious brewers who value origin flavour. Their Yirgacheffe offers delicate berry tones and a tea-like body, perfect for pour-over enthusiasts. For something richer, their Brazil Queen Manor brings chocolatey nuttiness with low acidity, great for espresso or French press. All three are sustainably sourced and roasted to highlight their natural profiles. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.