First of all, I have a confession to make. I’m not a coffee fan. Far too bitter for me. I’m definitely a plastic-free tea man!
Mrs. M, on the other hand, drinks gallons of the stuff. The soundtrack to a typical Miller family breakfast is her fancy bean-to-cup machine churning out cups of ’go get ’em’ joe!
Mrs. M loves her coffee machine. It saves her a fortune (bye, bye Starbucks), and she says the taste is better than anything a coffee shop can produce.
I love it because it’s pretty much zero waste. The coffee beans come in compostable bags, we use unbleached paper coffee filters that biodegrade, and the coffee grounds go in the food waste bin to be collected twice a month.
Well, they used to!
Around a month ago, Mrs. M came home from the hair salon and asked if I knew what plants like coffee grounds (it turns out she’d been reading an old magazine in the reception about how coffee grounds make excellent fertilizer).
I didn’t know, but it sounded like the perfect topic for an article. So here we are!
Believe it or not, many things can be done with coffee grounds, including using them to help plants grow.
In this comprehensive guide, I’ll discuss what plants like coffee grounds and how to use them to help your garden plants and houseplants thrive.
5 Houseplants that Like Coffee Grounds
- About: Christmas cacti are native to South America. They’re often grown as houseplants and can be used to decorate homes during Christmas. They need to be kept in a warm environment; the ideal temperature range for Christmas cacti is between 65 and 75 degrees Fahrenheit. Christmas cacti should be watered regularly but allowed to dry out completely between watering. Overwatering can lead to root rot.
- Light Needs: Bright but indirect.
- Ideal Potting Mix: 60% houseplant potting mix, 40% perlite.
- Coffee Needs: A generous sprinkling of used coffee grounds mid/late November will keep the plant looking its best throughout the holiday season.
- About: A Jade Plant is a succulent, meaning it stores water in its leaves. This makes it an excellent plant for people who often forget to water their plants or those who live in a dry climate. They need full sun and moderate watering (allow the soil to dry out between watering). Jade Plants can be propagated by taking stem cuttings and rooting them in moist sand or vermiculite.
- Light Needs: Bright but indirect.
- Ideal Potting Mix: 100% cactus potting soil.
- Coffee Needs: Fertilize with used coffee grounds every four weeks during the growing season (early spring to early fall).
- About: African violets (Saintpaulia) are a popular houseplant. They’re relatively easy to care for and come in various colors. To water an African violet, wait until the top inch of soil is dry to the touch. Then, water the plant until the soil is drenched. Be sure not to leave the plant sitting in water, as this can lead to root rot.
- Light Needs: Bright but indirect.
- Ideal Potting Mix: 50% peat substitute, 25% vermiculite, 25% perlite.
- Coffee Needs: A sparse sprinkling of used coffee grounds when the plant looks weary.
- About: Philodendron is a genus of flowering plants in the Araceae family. There are over 900 species, making it one of the largest genera in the family. They’re native to tropical and subtropical regions of the Americas, Africa, Asia, and Australia. Philodendrons vary in size from small tabletop plants to large specimens that can reach up to 20 feet in length. The leaves are usually large and lobed, with the leaf margins often being toothed or serrated. The flowers are small and inconspicuous and are borne on a spadix surrounded by a large, showy spathe.
- Light Needs: Medium bright but indirect.
- Ideal Potting Mix: 50% houseplant potting mix, 50% coco coir.
- Coffee Needs: A decent sprinkling of used coffee grounds every four weeks during the growing season (spring and summer).
- About: Peace Lilies are beautiful plants that make a great addition to any home. They’re perfect for beginners with their ability to tolerate a wide range of conditions.
- Light Needs: Bright but indirect, with occasional shade.
- Ideal Potting Mix: 50% coco coir, 25% perlite, 15% orchid bark, and 10% charcoal.
- Coffee Needs: A generous sprinkling of used coffee grounds in early Summer will really help with flowering.
6 Garden Plants that Like Coffee Grounds
- About: Hydrangeas prefer moist soil, so water them regularly. You may also need to fertilize them occasionally, especially if the soil is poor. In terms of location, Hydrangeas do best in partial shade. They can tolerate full sun, but they may not bloom as well. And finally, when it comes to pruning, you should do so in late winter or early spring.
- Light Needs: Anything from full sun to partial shade.
- Soil Needs: Moist, well-drained loam, sand, or clay-based soil.
- Coffee Needs: Fresh coffee grounds sprinkled sparingly around the roots.
Azalea And Rhododendron
- About: Azaleas and rhododendrons are flowering shrubs commonly used in landscaping. They both have beautiful blooms but bloom at different times of the year. Azaleas typically bloom in the spring, while rhododendrons usually bloom in the summer or fall.
- Light Needs: Full sun or partial sun.
- Soil Needs: Well-drained loam or sandy loam with a PH between 4.5 and 5.5 is ideal.
- Coffee Needs: Fresh coffee grounds.
- About: Camellias are a type of flower known for their beautiful petals. They come in various colors, including white, red, and pink, and can be found in tropical and temperate climates. Camellias are often used in wedding arrangements due to their delicate beauty.
- Light Needs: Full or partial shade.
- Soil Needs: Well-drained loam or sandy loam, or acidic clay.
- Coffee Needs: Fresh coffee grounds sprinkled around the roots.
Lily Of The Valley
- About: Lily of the valley is a low-growing flowering plant found in shady areas. They have bell-shaped flowers with six petals that are white or light pink. These plants grow from bulbs and like well-drained soil. Water regularly and fertilize twice a year. They can be propagated by division or seed. These plants are deer resistant and make an excellent ground cover.
- Light Needs: Loves shade!
- Soil Needs: Loose and well-drained.
- Coffee Needs: Used coffee grounds dug into the surrounding soil twice a year.
- About: Daffodils are one of the most popular flowers in the garden, and are straightforward to grow. They come in various colors, including yellow, white, and orange, and they can be planted in either spring or fall.
- Light Needs: Loves sun!
- Soil Needs: Can grow in most well-drained soil.
- Coffee Needs: Used coffee grounds sprinkled onto the soil at the end of winter.
- About: Cyclamen is a genus of flowering plants in the family Primulaceae. Cyclamen includes around 20 species of perennial plants that are native to Europe and the Mediterranean region. Cyclamen are popular for their flowers, often white or pink, with five petals and protruding stamens. The leaves are generally heart-shaped with a silver or green marbled pattern on the top.
- Light Needs: Thrives is a cool, shady location.
- Soil Needs: Well-drained, humus-rich soil.
- Coffee Needs: Fresh coffee grounds, used sparingly.
The Science Behind Why Plants Like Coffee Grounds
Coffee grounds are rich in many of the nutrients that many plants need to thrive, including:
Many of these nutrients are in a biologically immediately available state in coffee grounds, meaning the plants can absorb them quickly without too much effort.
9 Ways Coffee Grounds Are A Gardener’s Best Friend
Add Coffee Grounds To Your Compost Pile
If you have a compost heap, coffee grounds are an excellent addition. They help add nitrogen to the compost, which benefits plants.
Composting coffee grounds also help to aerate the compost and keep it from getting too compacted.
Mix Coffee Grounds Into Potting Soil
Coffee grounds can be mixed into potting soil to create a rich, fertile mix for houseplants.
To make your own potting soil mix, simply add one part coffee grounds to two parts potting soil.
Fertilize Acid-Loving Plants With Coffee Grounds
Unbrewed coffee grounds are great for acid-loving plants.
If you have such plants in your garden or home, simply sprinkle unbrewed coffee grounds around the base of them periodically.
This will help increase the soil’s acidity and make it more hospitable for these types of plants.
Use Coffee Grounds As A Pest Repellent
Coffee grounds can also be used as a pest repellent.
Sprinkle them around the base of plants susceptible to pests, such as slugs and snails.
They’re also an effective way to stop neighborhood cats from using your garden as a litter box.
Make A Coffee Ground Mulch
Mulching is an excellent way to conserve moisture in the soil and prevent weed growth.
Coffee grounds make an excellent mulch, as they help to retain moisture and keep weeds at bay.
To make a coffee ground mulch, simply spread a layer of coffee grounds around the base of your plants.
Brew A Strong Cup Of Coffee
This may seem like an odd tip, but it’s actually quite effective.
Brew a strong cup of cold coffee and pour it around the base of struggling plants.
The caffeine and nutrients in the coffee will help to perk them up and give them a boost.
Improve Soil Texture And Quality
You can also use coffee grounds to loosen lumpy soil and make it more permeable and accessible.
It’s particularly beneficial for heavy clay, chalk-based, or sandy soil.
Coffee grounds attract worms to your garden.
Worms are great for the soil, as they help to aerate it and make it more fertile.
Coffee Ground As Liquid Fertilizer
Dissolve coffee ground in water overnight to create your own liquid fertilizer.
A Note On Coffee Grounds Acidity
While it’s true that fresh, unbrewed coffee grounds are pretty acidic (a PH of under 5), the spent coffee grounds you get from brewed coffee (like to ones coming out of Mrs. M’s machine) are pretty neutral (a PH of around 6.5 - 6.8).
This means you should only use unbrewed coffee grounds on acid-loving plants, whereas brewed coffee grounds can be used on a much more comprehensive selection of other plants.
Frequently Asked Questions
What Are Coffee Grounds?
Used coffee grounds are the leftover coffee beans that have been roasted, ground, and brewed. Unused coffee grounds are ground coffee beans that have not been used to make a cup of coffee.
What Vegetables Benefit From Coffee Grounds?
Members of the tuber family, such as carrots and radishes, respond well to coffee grounds.
What Are the Disadvantages Of Using Coffee Grounds In The Garden?
Unused coffee grounds can make your garden soil too acidic for some plants. If in doubt, it’s best to do a pH acidic soil test before using coffee grounds in your garden.
The Final Word
So there you have it. A list of houseplants and garden plants that, in my experience and research, love a bit of coffee.
However, I’d advise caution before you go covering everything in your garden with coffee grounds. Like me, not every plant is a fan.
For example, this study concluded that adding coffee grounds inhibited the growth of broccoli, viola, sunflower, radish, and leek.
Also, don’t use too much.
Overloading your garden and houseplant with coffee grounds can result in them getting too much of a good thing. Which (as I’m all too familiar with when it comes to burritos and chocolate milkshakes) is not good for long-term health.
If you want to up your coffee fertilization game, I’d recommend starting with the plants mentioned in this article before branching out on your own and experimenting.
Get In Touch
Do you use coffee grounds in your garden and on houseplants? What do you find works best? Do you have any spectacular success stories to share?
I’d be especially interested to hear if you’ve had any joy with broccoli, viola, sunflower, radish, and leek. Drop me a line and let me know.