I bet there is a big crossover between people who love coffee and those who love gardening. Could the two possibly intersect? Coffee grounds are often advertised as one of those miracle garden tricks you can do right at home, but what plants actually like coffee grounds? Let’s find out!
A daily cup of coffee (or, let’s be real, two cups) can lead to a lot of coffee grounds. Why not try to use them up and let our plant babies benefit from them?
There are a ton of misconceptions and debates surrounding coffee grounds. What I can tell you is my personal experience with plants that actually like coffee grounds as well as some studies to show you where I’m coming from.
As a passionate gardener, I’m always looking for ways to naturally enrich my soil and stimulate plant growth. Over the years, I’ve discovered that used coffee grounds offer an easy, sustainable solution. Not only does repurposing this kitchen “waste” reduce landfill contributions, but the grounds also provide a wealth of benefits for a variety of plants. Their slightly acidic pH, essential nutrients, and organic matter improve soil structure and fertility. If you’re ready to unlock the secret power of used coffee grounds, keep reading to discover 25+ amazing plants that love this unlikely garden booster!
Why Plants Love Coffee Grounds
Understanding why coffee grounds make great fertilizer starts with their chemical composition. As the grounds break down, they release nitrogen, potassium, phosphorus, and other trace nutrients that are essential for plant growth and development. The organic matter in the grounds also improves soil texture, aerates the root zone, and enhances moisture retention.
Perhaps most importantly, the grounds create the slightly acidic soil conditions preferred by many plants. Coffee’s pH usually falls between 6.5 and 6.8 when fresh, lowering to around 6.2 as the grounds age. This mild acidity is perfect for boosting blueberries, azaleas, roses, and more.
Overall, amending your soil with used coffee grounds provides plants with a slow-release fertilizer packed with organic matter and beneficial acids Now let’s explore some of the top beneficiaries of this unlikely garden superfood!
1. Blueberries
Native to North America, blueberries thrive in acidic soils, making coffee grounds an ideal fertilizer. A sprinkling of grounds around your bushes provides nutrients for lush foliage and plump, antioxidant-rich berries. The acidity also helps blueberries absorb iron and other minerals. Grounds may even deter weeds when used as mulch!
2. Tomatoes
A coffee boost enhances tomato growth and fruiting. The nitrogen encourages healthy leaves and vines, while the grounds’ organic matter improves drainage and nutrient delivery. For tastier tomatoes, mix a handful of grounds into the planting soil!
3. Garlic
Garlic loves the nitrogen release from coffee grounds. The improved soil nutrition results in more vigorous bulbs and higher yields. Grounds also reduce soil compaction for better root development. Mix them into planting beds before setting out garlic cloves.
4. Carrots
These root crops thrive with the aeration and soil loosening provided by used coffee grounds. The nutrients give you long, straight, and vivid orange carrots. Fold grounds into your raised beds or carrot rows a few weeks before sowing seeds.
5. Peppers
Give your sweet and hot peppers a kick by working grounds into the soil before transplanting seedlings. The nitrogen and organic matter stimulate abundant foliage and improved fruiting. Grounds may also help repel certain pests!
6. Radishes
Quick-growing radishes receive a tasty nutrient infusion from used coffee grounds. The nitrogen accelerates top growth and root development, while the grounds’ texture improves the rooting environment. Your harvest will be crisp, colorful, and flavorful!
7. Cucumbers
These vining crops require excellent drainage and nutrient-rich conditions. Used coffee grounds enhance soil structure while providing a steady nitrogen release Your reward? More abundant, unblemished fruits on vigorous vines!
8. Cabbage
This brassica thrives with the nitrogen jolt provided by used coffee grounds. Work some into the soil before planting or side-dress transplants. The improved fertility and soil health mean bigger heads and sweeter flavor. An added bonus? Grounds may help deter cabbage worms and slugs!
9. Beets
Add used coffee grounds to your beet planting beds for better germination, seedling vigor, and yields. The nitrogen accelerates leaf growth, while the organic matter improves moisture retention and nutrient delivery to the developing roots. Just don’t overdo the grounds to avoid excessive soil acidity.
10. Lettuce
Provide mixed greens and lettuce an organic matter boost by blending used coffee grounds into the top few inches of your planting bed. The nitrogen feeds fast leafy growth, while the grounds’ texture improves drainage and nutrient absorption. You’ll enjoy tender, lush leaves!
11. Spinach
Used coffee grounds stimulate soil biological activity and provide readily available nitrogen, translating to fast, healthy spinach growth. Improved drainage and soil tilth also protect against fungal diseases. Incorporate grounds when preparing spring and fall planting beds.
12. Onions
Onions thrive with the slow-release nitrogen and trace elements from used coffee grounds. Healthier roots and more vigorous foliage result in bigger bulbs. Fold grounds into beds before planting or side-dress established onions. Just don’t overdo it, or flavor may suffer.
13. Strawberries
Used coffee grounds provide an accessible nitrogen source along with the acidic soil conditions strawberries prefer. Mix grounds into June-bearing beds in spring and day-neutral varieties in summer for sweeter, juicier berries. A coffee mulch also suppresses weeds.
14. Rhubarb
Scatter used coffee grounds around emerging rhubarb plants in early spring. The extra fertility powers leaf and stalk growth while the acidity benefits nutrient uptake. Your harvest will be abundant and flavorful. Don’t apply grounds after mid-summer to avoid delayed dormancy.
15. Asparagus
Give young asparagus plants an organic boost by working used grounds into the trench backfill. The nitrogen and trace elements stimulate spear production and overall vigor in the permanent planting. Established beds also benefit from a light spring dressing.
16. Citrus Trees
Oranges, lemons, limes, and other citrus trees thrive in somewhat acidic soil. Used coffee grounds help maintain the ideal pH while providing an infusion of nitrogen. Sprinkle them around the drip line and water in. Healthier roots and foliage result in more abundant fruit!
17. Azaleas
These flowering shrubs need acidic, well-drained soil. Used coffee grounds are the perfect solution! Scatter grounds around azaleas in early spring before the blooming period. The acidity benefits mineral uptake while nitrogen powers leaf and flower production. Gorgeous!
18. Gardenias
Like azaleas, gardenias flourish with used coffee grounds worked into the soil around their roots. The nutrients stimulate growth and flowering, while the mild acidity allows better iron absorption for lush, glossy leaves and vivid blooms. A beautiful pairing!
19. Hydrangeas
Used coffee grounds help hydrangeas absorb more aluminum, resulting in gorgeous blue blossoms on acid-loving varieties. The grounds also provide fertility for fabulous flowers and foliage. Sprinkle them around plants in early spring and work lightly into the top few inches of soil.
20. Hibiscus
Tropical hibiscus thrive when their soil is rich in organic matter and slightly acidic—both benefits provided by used coffee grounds. The nitrogen and trace elements also power more prolific flowering. For the best results, feed plants every month or so during the growing season.
21. Sunflowers
What better way to recycle coffee grounds than by using them on sunflowers? These nitrogen-loving giants soak up the steady nutrient release. Fold used grounds into planting beds and side-dress established plants for bigger, brighter blooms and thicker stems.
22. Dahlias
Scatter used coffee grounds around the base of your dahlia tubers in spring as growth resumes. The organic matter improves moisture retention and drainage, while the slow nitrogen release powers lush leaves and abundant flowers. Continued light feedings sustain their beauty!
23. Roses
Used coffee grounds provide the acidic soil conditions prized by roses. The nutrients also support healthier canes, leaves, and blooms. Work a handful into beds before planting and scratch grounds into the top inch around established plants in early spring and after pruning.
24. Lavender
Although lavender prefers neutral to alkaline soils, it tolerates slightly acidic conditions. Small amounts of used coffee grounds provide organic matter and slow-release nitrogen to stimulate plant growth. Just don’t overdo it, or foliage health and flower production may decline.
25. Lilies
Give your favorite lily varieties a fertility boost by sprinkling used coffee grounds around plants as growth resumes in spring. The nitrogen and trace elements enhance leaf and stem vigor, size, and flowering. Acid-loving Asiatic and Oriental hybrids benefit the most from the mild acidity.
How to Use Coffee Grounds in Your Garden
Now that you know which plants thrive with this unlikely fertilizer, let’s discuss easy and effective application methods:
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Mix grounds into planting beds and pots before seeding or transplanting. Focus on acid-lovers like blueberries.
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Lightly scratch used grounds into the top inch of soil around established plants. Target roses, azaleas, dahlias.
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Side-dress veggies and annuals with a thin layer of grounds mid-season for a growth and flowering boost.
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Create a nitrogen-rich compost or mulch by blending grounds with leaves, grass clippings, straw, etc.
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Brew a fertilizer tea by steeping grounds in water, then use it to feed plants every few weeks.
No matter which approach you choose, moderation is key. Excess grounds can over-acidify the soil or create drainage issues. I recommend limiting them to 20% or less of your total soil amendments and fertilizers. With a little experimentation, you’ll discover how coffee grounds can bring out the best in your garden plants!
How to Use Coffee Grounds
Unless you happen to own a coffee shop, the daily amount of coffee grounds you produce from a cup of coffee can be added to your compost or mixed directly into your gardening bed. Sprinkle it on the surface and then mix it in.
Remember, too much of a good thing is bad. The coffee grounds can build up specific nutrients and overload the plants. Or, it might compact and actually make your soil hydrophobic. No more than 20% of your compost should consist of coffee grounds.
Coffee Grounds Are Acidic…Sometimes
One of the biggest misconceptions surrounding coffee grounds is its acidity. A good cup of Joe tastes so strong partly due to its high acidity, which makes people believe that the coffee grounds will also be acidic.
The truth is that the acid in coffee is water soluble, and much of it goes into your coffee mug.
The pH of coffee grounds can be acidic after decomposing, but it can also be neutral and even alkaline at times. So overall, the acidity of coffee grounds is inconsistent, though it does tend to lean towards slightly acidic to neutral.
These 10 plants love coffee grounds! Using coffee as fertilizer in the garden!
FAQ
Which plants benefit most from coffee grounds?
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Acid-loving plants:As mentioned above, these are the primary beneficiaries.
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Tomatoes:While not strictly acid-loving, tomatoes benefit from the slightly acidic nature of coffee grounds and the nutrient boost they provide.
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Houseplants:Many houseplants, especially those that prefer acidic soil, can also benefit from coffee grounds, says The Sill.
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Root crops:Some sources suggest that coffee grounds can help loosen soil, which can benefit root crops like carrots and radishes, says Garden Design.
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Other benefits:Coffee grounds can also act as a natural fertilizer, repel slugs and other pests, and improve soil structure and drainage.
Which plants cannot use coffee grounds?
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Alkaline-loving plants:Coffee grounds are acidic and can negatively impact plants that thrive in alkaline soil, such as linden, ironwood, red chestnut, arborvitae, lilacs, lavender, and rosemary.
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Cacti and succulents:These plants prefer drier soil, and coffee grounds can retain too much moisture, potentially leading to root rot.
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Plants sensitive to acidity:Some plants, like tomatoes, are very sensitive to acidic soil and may experience stunted growth if coffee grounds are used.
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Plants with specific needs:Geraniums, asparagus, and other plants may experience growth inhibition or other negative effects from coffee grounds.
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Seedlings and young plants:Coffee grounds can suppress germination and slow the growth of seedlings.
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Mulch:Coffee grounds can be compacted and retain too much moisture when used as mulch alone, potentially harming plants.
Can I just sprinkle coffee grounds on plants?
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Benefits:Coffee grounds can improve soil texture and add organic matter. They also contain nitrogen, potassium, and phosphorus, which are essential nutrients for plant growth.
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Best Practices:
- Thin Layer: Avoid creating a thick layer of coffee grounds on top of the soil, as this can hinder water penetration.
- Compost First: Composting coffee grounds before using them in the garden can help ensure that the nutrients are readily available to plants.
- Balance with Browns: When composting, balance the nitrogen-rich coffee grounds with carbon-rich materials like dried leaves or newspaper.
- Thin Layer: Avoid creating a thick layer of coffee grounds on top of the soil, as this can hinder water penetration.
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Potential Issues:
- Water Resistance: A thick layer of coffee grounds can create a water-resistant barrier, preventing water from reaching the roots.
- Nitrogen Availability: While coffee grounds contain nitrogen, it may not be readily available to plants if applied directly to the soil.
- Caffeine: While caffeine in coffee grounds is generally not harmful to plants in small amounts, excessive amounts could potentially inhibit growth, according to a Reddit thread.
- Water Resistance: A thick layer of coffee grounds can create a water-resistant barrier, preventing water from reaching the roots.
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Alternatives:Consider using coffee grounds as a compost ingredient or adding them to a worm bin. You can also create a “coffee tea” by steeping grounds in water and using the liquid as a fertilizer.
What bugs hate coffee grounds?
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Mosquitoes:The strong aroma of coffee grounds, especially when burned, can mask the scents that attract mosquitoes and deter them from biting.
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Wasps and Bees:These flying insects are also repelled by the scent of coffee grounds, especially when burned, according to W & W Nursery & Landscaping.
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Slugs and Snails:The strong smell and texture of coffee grounds can deter these garden pests, creating an inhospitable environment.
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Ants:The scent and texture of coffee grounds, along with the acids they contain, can damage ant exoskeletons and deter them from entering your home or garden.
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Fleas:Some people have reported success in using coffee grounds to deter fleas from their pets.
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Beetles and Flies:The caffeine and diterpenes in coffee grounds can be toxic to these insects, and they will generally avoid areas where coffee grounds are present.
Are coffee grounds good for Roses?
Coffee grounds are a great source of nitrogen for your roses; however, be sure not to use too much because it may burn the roots of the bush. Roses also thrive off of organic materials so coffee grounds would be a great addition to their soil. 11. Peace Lilies
Which plants love coffee grounds?
Basil grows best in nitrogen-rich soil. Using coffee grounds as mulch or a compost ingredient can improve plant growth and flavor. Now that you know which plants love coffee grounds, let’s explore the best ways to use them effectively:
Can you put coffee grounds in your garden?
You may have heard the gardening tip about putting coffee grounds in your garden, but this technique should only be used in a specific situation. Coffee grounds are acidic, and if you put them on plants that like neutral or alkaline soil, they won’t be good for your plants at all.
What plants benefit from coffee grounds?
Coffee grounds can help gardenias and fuchsias bloom. They alter the pH of the soil ever so slightly but enough to really make a difference. Your gardenias will bloom pearl-like, vibrant flowers thanks to the nutrient boost and soil improvement that will come from the coffee grounds. Fuchsias thrive in slightly acidic soil and will benefit greatly from coffee grounds.
What plants don’t eat coffee grounds?
Here’s a list of some plants that don’t do with coffee grounds: Some flowering plants such as orchids, lavender, and black-eyed susan. Some vegetables like asparagus. Few types of herbs, such as ferns. Other plants such as devil’s ivy or pothos, cactus, century plants, ferns, and rosemary.
Can you grow sweet vegetables with coffee grounds?
They’re rich in vitamins A, C, and E. On top of that, they’re great providers of potassium, iron, and beta-carotene. Fortunately, you can’t only plant them in your garden, but you can also grow them indoors. The sweet veggies accept coffee grounds, and they show quick results with it.