What to do with your coffee grounds?

What are coffee grounds?

Coffee grounds are the solid, granular residue left over after coffee preparation. If you use a coffee machine, the spent coffee grounds will be compacted into cakes.

The antioxidant, anti-inflammatory, and antiviral properties of coffee grounds, thanks to their caffeine and phenolic compounds, make them beneficial for skin and hair. Caffeine boosts blood flow, giving a firmer, more radiant appearance. Environmentally, recycling spent coffee grounds reduces waste and limits chemical use.

Using your coffee grounds in the garden and soil

Coffee grounds as a compost activator

Many of you compost coffee leftovers after grinding them with your peelings. But did you know that coffee grounds are also an excellent compost activator? Worms are particularly fond of them.

Coffee grounds help worms digest more effectively. Sensitive to caffeine, they’re more active in transforming organic matter into rich compost. Don’t hesitate to add your coffee grounds to your compost heap or bin — they act as an excellent soil improver when mixed with other organic material, helping to aerate heavy soils and improve drainage. That said, coffee grounds are not a balanced fertiliser on their own: think of them as a nitrogen-rich supplement to be used alongside other organic matter, rather than a standalone feed.

Coffee grounds as plant food and fertiliser

Adding used coffee grounds to your acid-loving plants makes a perfect garden fertiliser. Used grounds contain around 1–2% nitrogen by weight, along with phosphorus, potassium, and trace minerals like magnesium and calcium — making them a genuine slow-release plant food.

One important note on acidity: after brewing, used grounds sit at a nearly neutral pH of 6.5–6.8. They won’t dramatically acidify your soil, but their nutrients and organic matter benefit acid-loving plants such as roses, azaleas, hydrangeas, and blueberries when applied correctly.

Application tips:

• Mix into garden soil rather than applying in a thick layer on the surface — dry grounds can form a water-repelling crust
• Keep coffee grounds to a maximum of 20% of your compost mix
• For a liquid fertiliser, steep 2 cups of grounds in 5 gallons of water overnight, strain, and use to water containers or garden beds
• Apply to outdoor plants no more than once a month; every two months for indoor plants

Avoid using directly around: tomatoes, seedlings, lavender, rosemary, and geraniums, which prefer neutral to alkaline soil.

Coffee grounds for grass, roses and repelling insects

Coffee grounds are also an excellent insect repellent. You can use them against slugs, snails, caterpillars, ants, mosquitoes and fleas. Scattering grounds on grass can deter pests while feeding your lawn at the same time.

Our mosquito repellent tip? Burning a cup of coffee grounds in a container with a match or lighter will help combat mosquito infestations—the smoke smell scares them away.

How to reuse coffee grounds as a beauty product

Coffee grounds offer a natural, chemical-free alternative to commercial beauty products, with benefits for both skin and hair.

Coffee grounds as an exfoliating body scrub

The coarse texture of coffee grounds makes them an excellent natural exfoliant for your face and body. Thanks to the caffeine they contain, they cleanse deep down and have a rejuvenating effect on the skin. The gentle scrubbing action also helps reduce the appearance of cellulite by stimulating blood circulation.

Mix your used grounds with a carrier oil like olive oil or coconut oil, or try honey for added moisture. Massage the mixture onto damp skin in circular motions, then rinse thoroughly. In no time at all, pores are unclogged and a tightening effect guaranteed! This simple body scrub replaces multiple store-bought products while reducing potential allergic reactions to chemical ingredients.

Coffee grounds for hair growth and colour

Coffee grounds promote hair growth and soothe itchy scalps while caring for oily hair. Simply apply as a conditioner to wet hair, massage into your scalp, and rinse. The grounds exfoliate the scalp and stimulate blood circulation, boosting growth.

You can tell its colouring properties just by looking at its rich brown colour. It revives colour and restores shine to brown and dark hair, camouflaging grey hair and slowing its appearance naturally.

Recycling coffee grounds as a household product

It’s hard to believe, but it’s true. Coffee grounds are an excellent daily cleaning product. Although sceptical at first, some members of the team have tested it, and their feedback is very surprising.

A super deodoriser

Coffee grounds remove stubborn garlic, onion or fish odours from your hands or even your fridge. By filling a bowl with used coffee grounds, you can deodorise everything without replacing the old smell with coffee. Coffee grounds absorb unpleasant odours and last for about 2 weeks. When the smell returns, it’s time to change the contents of the bowl!

Drain maintenance

Leftover coffee helps to prevent clogging and eliminate unpleasant odours. It’s the best way to reduce the risk of blockages and avoid expensive corrosive products. Just put a tablespoon of grounds in your sink and run very hot water for about 2 minutes. This simple process allows the coffee grounds to flow down your pipes and clean them naturally while absorbing odours. Repeat once a week to prevent your sink from clogging up with grease.

Coffee grounds to polish and clean furniture

Wet coffee grounds can be used to polish fine scratches on wooden furniture. Mix the grounds with a pinch of salt for better results, then rub gently with a cloth in small circles. They can also be used as an abrasive cleaner for greasy stoves.

Coffee grounds as a natural dye

Coffee grounds work brilliantly as a natural dye for fabrics. Simply soak your clothing or fabric in a mixture of coffee grounds and water, then let it dry for a unique, earthy colour. If you are looking for a quality machine to brew your daily coffee, check out our Kottea Oslo review.

Frequently asked questions about used coffee grounds

Which plants do not like used coffee grounds?

While many plants thrive with coffee grounds, some houseplant varieties and young seedlings don’t appreciate the acidity. Lavender, geraniums, asparagus ferns and rosemary prefer neutral to alkaline soil, so fresh coffee grounds can throw off their pH balance. Gardeners experimenting with new plants should test soil pH first—especially before adding grounds to containers or around delicate seedlings. When in doubt, stick to acid-loving varieties like azaleas and camellias.

How to store used coffee grounds?

Spread used coffee grounds thinly on a baking tray and let them air-dry completely. Once dry, transfer them to an airtight container—a glass jar or sealed plastic tub works perfectly. Stored this way, they’ll stay usable for several weeks without developing mould. If you’re collecting grounds over time, just add each batch to your container as you go.

What animals will coffee grounds keep away?

Used coffee grounds work as a natural deterrent for several common garden pests. Cats often avoid areas where you’ve sprinkled grounds, making them useful for protecting flower beds. Slugs and snails dislike the gritty texture and caffeine content. The strong scent also repels certain insects, including ants. While not foolproof, this eco-friendly approach gives you a chemical-free first line of defence.

Can I just sprinkle used coffee grounds in my garden?

Yes, sprinkling a light layer of used coffee grounds directly around your plants is the easiest way to put them to work. That said, mixing them into garden soils gives you better results—the grounds integrate more evenly and won’t form a water-repelling crust on the surface. Use a thin layer and refresh it monthly rather than piling it on thick.