How to Fertilize Your Plants with Used Coffee Grounds

At Muskoka Roastery, we believe in enjoying every cup of coffee to the fullest—and that includes giving new life to your used grounds. If you're a coffee lover and a plant parent, you'll be happy to know your morning cup can do more than just wake you up. When used the right way—it can help your houseplants thrive.

Here's how to turn your used Muskoka Roastery coffee grounds into a plant-friendly fertilizer and what to keep in mind while doing it.

1. Stick with Used Grounds (Not Fresh!)

Fresh coffee grounds might smell amazing, but they're not ideal for most plants. They tend to be high in acidity and caffeine, which can harm your leafy friends. Used coffee grounds, on the other hand, are less acidic and more plant-friendly.

Unless you're growing acid-loving plants like hydrangeas, azaleas or blueberries, we recommend saving only the used grounds from your morning coffee.

2. Add Used Grounds to Your Compost

One of the best ways to reuse coffee grounds is by adding them to your compost. They mix beautifully with vegetable peels, fruit skins, and other natural waste, creating a nutrient-rich mixture your plants will love.

Once your compost is ready, blend a small amount into your potting soil. Just be careful—not too much! Overdoing it can cause nutrient overload or make the soil too water-retentive. If you’re worried about overwatering, mix in some coarse sand or perlite to keep things airy.

3. Try a DIY Liquid Fertilizer

No compost pile? No problem. You can make a liquid fertilizer instead!

Mix about one teaspoon of used coffee grounds per gallon of water, let it steep for a couple of days, and strain it through cheesecloth. This nutrient-rich "coffee tea" makes a gentle, plant-safe watering solution. Bonus: it's totally free and super eco-friendly.

4. Sprinkle Grounds Sparingly on Soil

You can also sprinkle used coffee grounds directly on top of the soil—just don’t overdo it. A thick layer can clump together and block water and air from reaching your plant’s roots. Think of it more like a seasoning than a full-on topping.

5. Don’t Forget Other Nutrients

Used coffee grounds are a great supplement, but they won’t give your plants everything they need. To keep your green friends growing strong, use a balanced fertilizer now and then, or repot with fresh soil once in a while.

From Brew to Bloom 

Using your Muskoka Roastery coffee grounds as plant fertilizer is a simple, sustainable way to nourish your plants and reduce waste. Just remember: moderation is key, and always keep an eye on how your plants respond.

So go ahead—enjoy your coffee, then give a little love back to the earth. Your plants (and your compost pile) will thank you.