*This site contains product affiliate links. We may receive a commission for purchases made through these links. This, however, has no bearing on our reviews and comparisons. Disclosure
If you are a coffee drinker, then you’re probably already familiar with all the used coffee grounds that up in your kitchen trash. This is, of course, only if you are not using a composting system for your food waste. But those grounds aren’t just any old garbage—coffee grounds are actually something of value!
What if we could repurpose these grounds for in exchange for a green thumb? Many people are aware of the benefits of coffee grounds for composting and gardening, but are coffee grounds good for houseplants?
It turns out, yes; they are! There are many ways to use those coffee grounds and an organic houseplant fertilizer is one of those ways.
Coffee grounds are one of the most popular organic fertilizers and provide many benefits to plants, including faster plant growth, less need for pesticides, and better resistance against pests.
Because coffee grounds are nutrient rich and provide nitrogen, phosphorus, potassium, magnesium and calcium, they make an ideal soil additive for organic plant soil.
When you are growing houseplants, this is the perfect supplement for helping them grow strong and healthy! Also, coffee grounds contain small traces of theobromine, which has been shown to have beneficial effects for plants.
You can improve these benefits even more when you mix wood ash, worm castings, or compost with your coffee grounds. The pH of the mixture should be around neutral to maximize the benefits of coffee grounds.
A good ratio of fertilizers is 40% worm castings, 30% compost, 30% coffee grounds. Adding these ingredients to your potting soil creates an amazing growing environment for your plants.
You should apply coffee grounds in moderation though, since they can reduce the need for fertilizers. Adding too many grinds can also increase the amount of water required for sustainability. Negatives aside, adding coffee grounds is an inexpensive and thrifty way to provide nutrients to your houseplants.
“Coffee grounds are one of the most popular organic fertilizers and provide many benefits to plants, including faster growth, less need for pesticides, and better resistance against pests.”
Other Benefits of Adding Coffee Grounds to Your Houseplants
The benefits of adding coffee grounds to soil for your plants are many. They are rich in nitrogen, potash, and phosphate- all important nutrients for plants to thrive.
Similar to mulch, coffee grounds are also porous, which means they will help keep moisture in the soil—great for houseplants that need regular watering.
Lastly, think about how much money you’ll save on fertilizer!
How To Apply Coffee Grounds to the Soil of a Houseplant
As mentioned, coffee grounds are great for adding to soil because they are rich in many nutrients, but if not done properly, you could end up damaging your houseplants.
Directly applying coffee grounds to the soil is not the most recommended option, as it can cause fungus buildup, excessive moisture retention, and impair plant growth.
The better solution is to compost your coffee grounds first. However, if applying them directly to the soil is your only option, make sure you add only a ¼” layer or less. Then add a 4″ layer of mulch on top.
How Much and How O
How Much and How Often Should You Use Coffee Grounds on Your Houseplants?
Try to shoot for about an inch of compost, gently mixed into the top layer of the soil (avoiding disruption of the root system), at least twice a year for optimal results. Too much compost can actually hurt your plants, so it’s best not to overdo it. When you make your compost pile, coffee grounds shouldn’t account for any more than 20% of the compost materials.
This natural fertilizer is a great and safe alternative to using chemical fertilizers on houseplants, especially if you have pets or small children.
If you don’t drink coffee and you’re wondering how you’ll get a hold of all these coffee grounds, chances are you know someone who does. Kindly ask them for their old coffee grounds. Close relatives and neighbors are a great place to start.
Also, you might try a few local restaurants. Most would probably be happy to give you their coffee grounds for free.
The Benefits of Using Coffee Grounds in Your Outside Pots, Compost Pile, and Garden
Your garden and planted pots outside are also a great place to put any leftover coffee grounds (I mean, one only has so many houseplants, right?).
Applying your extra grounds outside can be very beneficial in deterring bugs. The flies and gnats that love to plague your outdoor living space will stay far away from plants you have treated with coffee grounds.
In addition, the acidity of the coffee grounds helps deter slugs naturally rather than using commercial chemicals that can harm pets and wildlife. Some gardeners even add a bit of leftover brewed coffee into the soil to help with the acidity levels. This can be especially effective when starting seedlings that require more acidic conditions than mature plants.
Coffee grounds also add a nice little sprinkle of nitrogen into your garden or yard, helping to keep your plants healthy and lush looking. Adding a handful of leftover coffee granules around your outdoor plants will provide a nice boost for them.
Though experts refer to coffee grounds as acidic, they’re referring to the pH levels and not the kinds of acid found in household cleaners. Coffee grounds actually have slightly more alkaline than acidic, so it is perfectly safe to use with most plants without fear of harming them with too much acidity.
Sometimes, if you have a particular plant that requires acidic soil conditions, you can use coffee grounds to balance out the pH levels in your garden beds or planters.
Also, if you have an herb garden, or are thinking of starting one, coffee grounds can be very beneficial to herbs that prefer slightly more acidic soil, like basil and oregano.
As mentioned above, they are a great addition to a compost pile. So if you have any leftover coffee grounds you can’t immediately use on your houseplants, this will be an efficient use for them.
Other Creative Uses for Fresh and Used Coffee Grounds
Remove Fleas from Your Pet
You can also remove fleas from your pet by rubbing coffee grounds throughout your pet’s fur after shampooing. You can then rinse them off and allow your pet to dry as usual.
Some even claim that coffee grounds may add smoothness and shine to your pet’s coat. However, there’s not much research to back this up.
Coffee grounds may be less effective than a prescription product, so if your pet has fleas, and this treatment does not work, contact a vet to discuss alternative options.
Be sure you’re only externally using coffee grounds, as they can be toxic to dogs if consumed.
Neutralize Odors from Your Hands and Home
It’s not uncommon to have the lingering smell of garlic or fish on your hands after cooking a meal. Coffee grounds can remove these odors from your skin. Simply rub them on your hands and then rinse with warm water.
They can also remove cooking smells, like fish, onion, and garlic, from your home. Place some coffee grounds in ramekins and place them around your home to neutralize these odors.
Repel Annoying Insects and Pests
One means of repelling annoying pests like insects is to scatter coffee grounds around targeted areas. Coffee, because of the caffeine and diterpenes that it contains, is very toxic to bugs.
Coffee grounds have proven effective at deterring mosquitos, fruit flies, beetles, and other pests.
Just set out containers of grounds or sprinkle them around outdoor seating areas.
You can also minimize pests like slugs and snails in your garden by scattering them around your plants.
Compost It To Use Later
Many people use coffee grounds in their compost pile. The grounds are rich in nitrogen, which is needed for plants to grow. Coffee grounds also contain chitin, which is an insect natural-control agent.
Coffee grounds can also be used in a compost pile to help break down leftover food scraps like banana peels and eggshells, which decompose too slowly on their own.
Use It as a Natural Cleaning Scrub
Coffee grounds act as a natural cleaner because of their abrasive properties. They can remove buildups on hard-to-clean surfaces, sanitize, and even polish cookware. They’re also good for polishing stainless steel and removing tarnish from copper and brass.
They might even help you clean up that nasty grill you’ve been neglecting!
Keep in mind though, you should not use coffee grounds on any kind of porous material, as they cause brown stains. Always test in a small, inconspicuous area first.
If you’re a fan of natural beauty products, coffee grounds may be the answer to your exfoliating needs.
Coffee grounds are abrasive, which helps to slough off dead skin cells and dirt from the epidermis.
Simply combine coffee grinds with a little water or coconut oil and massage them directly onto your body and face.
In addition, the antioxidants in the caffeine can help fight free radicals that cause cellular damage, tightening up pores and soothing sensitive skin while simultaneously fighting wrinkles.
A Scrub for Your Pots and Pans
Coffee grounds are abrasive enough to be used as an all-natural way to scrub pots and pans. Just place coffee grounds at the bottom of your pot or pan and add water to create a cleansing paste. Scrub as usual, then rinse with warm water, and dry to reveal sparkling clean pots and pans!
Confused? Don’t be.
When added to a marinade, coffee grounds can help tenderize meats by breaking down long strands of proteins with their natural enzymes and acids.
Therefore, it can help make tough meats, like lean beef and venison, more tender. Also, it will flavor the meat in a unique and delicious way.
So your morning cup of Joe might end up as an impressive addition to your cooking arsenal.
Coffee grounds are beneficial for your other indoor plants as well. If you have an herb garden, feed your plants with coffee grounds by mixing them in the soil.
Just remember that coffee grounds are acidic, so it is a good idea to mix them with a little peat or coconut coir to balance the pH level.
Adding this mixture to your indoor plants can help to suppress the growth of pathogens that can cause disease and harm plant roots.
Put That in Your Pipe…No, Don’t Really Do That
Coffee grounds are a great way to help your houseplants (and you) thrive, and also have many other brilliant uses around the home.
So, if you’re looking to give your plants some extra love this season, consider adding some composted coffee grounds to the soil.
To your coffee journey!
Clint Doerfler is the founder of Coffee Gear Gurus® and has been obsessed with everything coffee since a very young “growth-stunting” age. He is passionate about helping fellow coffee lovers make amazing coffee at home, no matter what their level of experience.