What do you do with your spent coffee grounds? If you’re like most Americans, you probably toss them. But not only does this practice contribute to our growing trash problem, it’s also a waste of a surprisingly useful resource!
In fact, there are loads of ways to use coffee grounds around the house and in the garden. You’ll be surprised to learn that coffee grounds are not only a great (and basically free!) soil amendment, but they can also be used in a number of other ways as well.
Want more? If you don’t drink coffee, or want more grounds than your household produces, you may be able to collect free grounds from your neighborhood coffee shop and put them to work for you!
#1. Repel Pests Naturally
Coffee acts as a natural bug deterrent, making it a perfect way to keep insects out of your home and garden. This is because it contains natural compounds like caffeine and diterpenes. Mosquitos, beetles, and fruit flies will all try to avoid coffee, so consider setting out a bowl of used grounds in places you don’t want them to land. You can also sprinkle some throughout your plantings to deter slugs and snails.
You can also keep the neighborhood kitty out of your garden by mixing your grounds with chopped orange peels and then scattering them onto the soil.
#2. Fertilize Your Soil
Incorporating coffee grounds into your fertilization routine can be a smart move. Blend your grounds with dead grass clippings and brown leaves, and spread the mixture around your plants for a beneficial boost of potassium, nitrogen, calcium, iron, magnesium, and more.
As an added benefit, the grounds might help absorb heavy metals that taint your soil. If you also want to enhance blooming and fruiting, be sure to incorporate lime or wood ash into the fertilizer, as well.
#3. Compost It for Later Use
If your grounds collection is starting to build up, then consider incorporating it into your compost pile. Studies show that adding grounds to compost as your “green” material makes it richer in nutrients than it would be otherwise. What ratio is best? Research found that compost made with 40 percent coffee grounds produced the best quality (and fewer greenhouse gasses) than other blends—so bulk up your compost pile with coffee!
#4. Cultivate Mushrooms
There’s no reason to think that mushrooms are outside your talents for cultivation—your old coffee grounds are a stellar growth substrate for getting a crop. Not only are they a concentrated nutrient source, but the grounds are sterilized during the brewing process, which means that you can use them without any further processing.
While most types of mushrooms will grow on coffee grounds, beginners tend to get the best results from shiitake or oyster varieties. You’ll need about five pounds of grounds to get the process started, so start a collection or hit up your local coffee shop and request their spent beans. Once you have enough to begin, this article will walk you through the cultivation process.
#7. Make It Easier to Find Worms
For the fishing enthusiast, finding a reliable supply of worms for bait isn’t always easy. If you maintain a worm bed to keep worms within reach, adding spent coffee grounds to the mix will improve their habitat space and grow their population. The grounds also work great in vermiculture systems!
#8. Absorb Food (And Other) Odors
Considering how incredible coffee smells first thing in the morning, you might be surprised to learn that old grounds are a time-tested strategy for removing unpleasant odors from your kitchen. This is because coffee grounds contain nitrogen which, when combined with carbon, can remove bad-smelling sulfur gas from the air.
If you want to relieve your refrigerator of a foul scent, load up an open container with old grounds and put it in the back. Switch out the grounds every few weeks, and you’ll be surprised by how fresh your fridge continues to smell. (When you’re done with them, be sure to compost them or re-use them again for one of the other purposes mentioned in this article!)
Another option is to dry out your grounds and place them in old socks to use as a portable air freshener in your car, closet, gym bag, or dresser drawers.
And, after chopping onions or garlic, washing your hands with old coffee grounds can remove most of the scent.
#9. Use Spent Coffee Grounds as a Natural Abrasive for Scouring Pots and Pans
No one likes to deal with a dirty kitchen, but coffee grounds can remove much of the physical work for you. Coarse ground beans (the kind you use in the French Press) are naturally abrasive, but not to the point that they put your surfaces at risk. This makes them ideal for scouring everything from countertops to crusty pots and pans to remove build-up. Simply add a few teaspoons of grounds to a cleaning cloth and scrub away before rinsing thoroughly.
#13. Add It to Homemade Candles
For those who want to enjoy the smell of coffee without a dose of caffeine, you can collect old grounds to incorporate into handmade candles. The process is surprisingly easy—especially if you follow these instructions.
#15. Treat Fleas on Your Pets
This versatile material also works well as a flea treatment for dogs. Simply shampoo and rinse your dog like usual, then rub in the grounds, taking care to rinse them off at the end. The treatment is likely to deter fleas from your dog’s fur, and it can lead to a silkier coat, as well.
Note: Coffee grounds can be toxic to your dog if ingested, so be sure to keep the grounds away from the mouth and to rinse the coat thoroughly when you finish.
#10. Give Yourself a Facial!
Thanks to its natural abrasiveness, coffee grounds make a stellar facial scrub. Blend 2 tablespoons of spent grounds with cocoa powder and add 3 tablespoons of whole milk and a tablespoon of honey. Massage the luxurious mixture into your face with gentle circular motions and rinse thoroughly once you feel restored.