Coffee grounds are excellent fertilizers for crops, houseplants and garden flowers. They are basically a concentrate of nutrients, and they are cheap, “green” and ready to use.
They also smell nice, unlike other fertilizers. But do you know how to use them? Do you know which plants really like them?
Coffee grounds are excellent for all plants when mixed into the compost or added to the ground. There is a huge difference between new and used coffee grounds. These can be divided into four categories:
Keep reading to know what plants like coffee grounds and things to keep in mind when using coffee grounds as fertilizer.
Why Coffee Grounds Are Good For Plants
You know that coffee grounds are like “gold dust” in gardening; they are like energy boosts for plants.
You must have seen them in many pots and gardens, or maybe you have that friend who grows has houseplants that grow out of coffee grounds…
But why exactly are they so good? Let me tell you…
Coffee Grounds Are Rich in Nutrients
Some of the minerals contained in coffee grounds are essential to plants’ growth, in fact they are very, very rich in the following:
You have NPK (the basic, the main nutrients for plants, nitrogen, phosphors and potassium). Talking of nitrogen, 2% of all the volume of coffee grounds is made up of this most fundamental of nutrients! And that’s a lot!
But you also get some of those nutrients plant need in lower quantities but that are essential for their health, like magnesium and calcium. Finally, you also get some rare minerals like chromium.
Many Nutrients in Coffee Grounds Are Ready for Plants to Absorb
When you give coffee grounds to your plants they can start using them, “eating them” straight away.
You see, if you add organic matte to the ground you need to wait till it decomposes before your plants can actually use them. But many of the minerals in coffee grounds are ready food for plants.
For this reason, you can use coffee grounds for soil improvement with quick results.
Coffee Grounds Clean the Soil from Pollution!
You didn’t expect that coffee grounds are actually a way to fight the pollution in your soil, did you? They have a very special quality: they can absorb heavy metals, which are soil pollutants. We are talking about lead, mercury and cadmium, but also excessive lead and zinc.
Coffee Grounds Improve Soil Texture
You can also use coffee grounds to break up lumpy soil and make it loose, permeable and easy to work. They are especially good with heavy clay and chalk based soil for this.
They have a similar effect as that of sand: they break up the hard and impermeable pebbles of soil and improve aeration and permeability.
Coffee Grounds Attract Worms
Worms are wonderful soil fertilizers and they go mad for coffee grounds. You want to have a healthy soil, by which we mean a soil that can grow its won fertility.
Otherwise you end up in a negative cycle. You want your soil to have all the microorganisms it needs, but also worms, fungi and other creatures that decompose organic matter and make the nutrients available to your plants.
And worms are your best friend as a gardener!
Coffee Grounds Keep Slugs and Snails Away!
Coffee grounds are also good as pest control: snails and slugs hate the texture of coffee grounds. So, some gardeners like to scatter coffee grounds around crops that snails and slugs love a lot.
Especially tender leaves like lettuce, young cabbage, kale etc. are real favorites of snails and slugs.
No need for chemicals that pollute your soil if you just drink a few coffees and keep these annoying little leaf munchers away…
These are all the benefits of coffee grounds added to the soil. But did you know that they are excellent for compost too?
Coffee Grounds In Compost
Coffee grounds are an excellent ingredient for compost too. They have a very special property, on top of being super rich in nitrogen and other nutrients, they also encourage those microorganisms that decompose organic matter.
You only need to sprinkle them over the compost heap, in a thin layer or scatter them. Make sure you don’t just “lump them in”. They work better when they are distributed evenly and thinly.
Coffee Grounds Are Green (!!!) Compost
“No, coffee grounds are dark brown, not green,” you may say, but this does not apply to “compost colors”. Compost colors are based on the two main nutrients we mix in: brown is carbon rich matter while green is nitrogen rich matter.
This is actually true most of the time: if you throw in fresh leaves, they are rich in nitrogen and green; if you throw it brown organic matter, you will add lots of carbon.
But coffee grounds are an exception: they are brown in color but rich in nitrogen, so they count as green compost.
This leads us straight into the next point, which is how to use coffee grounds.
How To Use Coffee Grounds Properly
You need to use coffee grounds properly if you want to have optimal results with your plants. Coffee grounds, in fact, are very powerful and nutrient rich, and they need to be used with care.
To start with, remember that coffee grounds are “green compost”. This means that to give your plants a balanced diet, you need to add “brown compost” or carbon rich organic matter to your coffee grounds.
Cut up some dry leaves and mix in the coffee grounds before adding them to the soil. Any other carbon rich material will do, but dry leaves mix in very well with coffee grounds.
Only use a small amount of coffee grounds. So, no, the idea if growing plants directly in coffee grounds is not good gardening. Why? The same reason why they are so good: too much nitrogen. Let me explain.
Nitrogen is the nutrient plants need most. But… if plants have too much nitrogen in the soil they do not develop their roots.
They have no reason to, because all the nitrogen they need is nearby. And this is a major problem.
When the nitrogen finishes, the plants don’t have a well developed root system and they will suffer… even die!
You can add coffee grounds to the surface of your soil. This is a good way to improve your soil’s nutritional levels and texture.
They will slowly mix in and they will leach the nutrients into the soil. Do not nix the coffee ground into the soil; it is best to let the nutrients mix in the soil with rain and irrigation.
Even in this case, only scatter a thin layer of coffee grounds onto the soil. Give a “gentle boost” to your plants. Anything heavy may affect your plants’ growth.
Coffee Grounds and Soil pH
What is the pH of coffee grounds, and will it change the soil’s acidity levels? It depends… Let me explain to you.
This means that you can use used coffee grounds with almost all plants, but you can only use new coffee grounds with acidophiles.
Acidophiles are plants that love acidic soil, for example azaleas, rhododendrons, camellias, heather, nasturtium, hydrangeas, fothergillas, holly, gardenias, caladium.
Most vegetables like soil on the slightly alkaline side, but radishes, parsley, potatoes, peppers and rhubarb like acidic soil.
Similarly, many fruit trees will prefer neutral soil, but raspberries, blueberries, gooseberries, cranberries and currants will appreciate some acidity.
Now, of course most people would never consider using fresh, unused coffee grounds in their garden. It’s just very expensive. You can make your soil acidic with tea, lemon peels etc., and they are all much cheaper than coffee grounds. But the choice is yours.
Now, you know why coffee grounds are good for plants; you know how to use them; we have also mentioned some plants that particularly love them… shall we now look at some of these plants in detail?
20 Plants That Love Coffee Grounds
Our selection of 20 plants that really will reward you if you feed them with coffee grounds in the four categories has some household names, but also some unexpected entries, and here it is.
Garden Plants That Love Coffee Grounds
Coffee grounds can do wonders to your garden plants, and some of them more than others. Acidophiles will even like fresh coffee grounds, and there are quite a few of them in gardens and parks!
1: Azalea and Rhododendron (Rhododendron spp.)
Azaleas and rhododendrons are now the same genus of plants, but azaleas are particularly hard to grow in gardens. They are wonderful but in the whole more delicate than rhododendrons.
One of the tricks to keep azaleas happy is to have very nutrient rich but also very, very loose and well aerated soil!
They also like very low soil pH levels, between 4.5 and 5.5. It all needs to come together or they will become ill and weak. Their roots are delicate, and they cannot perforate heavy soil, like clay or chalk….
Coffee grounds make azaleas (and rhododendrons) very happy indeed and they will thank you with brightly colored blooms!
2: Camellia (Camellia spp.)
Camellia is an coffee grounds loving plant. It can make any garden look stunning, but it too is very delicate. It is an acidophile and unless the conditions are right you get yellowing leaves and, a tell tale sign, the buds form but dry up before opening.
This happens very often, and if this is the case with your camellia shrub, coffee grounds, even raw and new, can give it nutrients and correct the soil’s acidity in case.
Sprinkle coffee grounds by the base of the plant, making sure they are thin but cove all the the area of the roots.
3: Hydrangea (Hydrangea spp.)
Hydrangea is a plant synonymous with long and large blooms, freshness and large gardens and parks it too loves coffee grounds.
Unlike azaleas and camellias it is not very delicate and it can grow in different growing conditions, preferring an acidic or neutral soil.
But if you want your hydrangea to give its best, keeping its fresh herbaceous foliage green and long, round inflorescences bright and lively, a good sprinkling of coffee grounds at the base of the plant can go a ling way!
4: Lily of the Valley (Convallaria majalis)
Lily of the valley is a small garden plant, unlike hydrangeas and rhododendrons, but like them it appreciates coffee grounds.
This underbrush flowering perennial has beautiful bell shaped flowers, usually white. There is also a pastel lilac variety, Convallaria majalis rosea.
It is synonymous with dappled shade under tall trees, and a very traditional flower, also knowns for its medicinal properties.
It can grow in acidic, alkaline or neutral soil, but it prefers very loose and “brittle” soil. Coffee grounds give it both the texture it enjoys and the rich nutrients it likes.
5: Cyclamen (Cyclamen spp.)
Cyclamen is a special flower and it likes coffee grounds! It too is typical of wooded areas, like the lily of the valley.
But cyclamen can grow where almost no other flower does: under conifers where needles cover the ground and make it very acidic.
For this reason, cyclamens even like being fed some fresh coffee grounds from time to time.
Of course, while some cyclamens like Cyclamen coum are garden plants, there are others that are more common as houseplants. Don’t worry; they too love coffee!
6: Daffodils (Narcissus spp.)
Even daffodils, the sweet scented flowers we associate with spring, love coffee grounds. Daffodils are very undemanding to be honest.
In most gardens, all you need to do is plant a few bulbs and wait till they propagate and give you a sea of fresh smelling flowers every spring.
So maybe you will forget about them and you will be amazed year after year when they come back.
But if you want to give them a little present every now and then, just sprinkle some coffee grounds over the soil at the end of winter, when they are about to wake up…
Vegetables That Like Coffee Grounds
You can use coffee grounds in your vegetable garden too. In fact, most vegetables will like some extra nutrition with used coffee grounds, though few will stand fresh coffee grounds.
This is because most vegetables like a fairly alkaline soil pH, or neutral to alkaline.
On the other hand, many vegetable plants have a short life cycle, so, the will enjoy a boost of energy for their final sprint, just before you harvest them. And here are some that really like a bit of coffee.
1: Tomato (Solanum lycopersicum)
Tomatoes need lots of energy to grow and coffee grounds are really welcome. Every gardener knows that tomato plants eat a lot and drink a lot. On the other hand each vine can give you so much in terms of harvest!
So, because they need all the help you can give them, it would be a good idea to scatter some used coffee grounds round each tomato plant when they start blossoming, when the first fruits come and then again once or twice when they are fruiting. This way you will help them along till late in the season.
2: Potato (Solanum tuberosum)
Potatoes are closely related to tomatoes and they too love lots of energy and coffee grounds. In fact they are the same genus.
The tubers underground need an awful lot of nutrients to swell. In fact, they are like “energy banks”. What is more, potatoes like very loose soil. This is necessary to allow the tubers to swell with no obstacles.
Add coffee ground to the soil before planting your potatoes. Then, repeat it every 4 weeks all the way to harvest time. You will get bigger and more nutritious potatoes when you finally uproot the plants!
3: Radishes (Raphanus sativus)
Radishes really make a dash for it! In about three weeks from seeding, they are ready for the picking. For this reason, any help along the way in this very short time is welcome.
Think about it… in 20 days or so they need to grow their leaves and at the same time pack their juicy roots with as much energy as they can…
Give them a head start by adding some used coffee grounds to the soil just afters sowing them. The ready to use nutrients in the coffee grounds will be really welcome and you will see the difference in your crop!
4: Broccoli (Brassica oleacea var. italica)
Broccoli is super nutritious and packed with vitamins, and it too likes a boost of energy from coffee grounds.
In fact if you want to help them pack all their nutrients into their delicious florets (stalk and leaves) you can use coffee grounds to do just that!
Keep adding some used coffee grounds to the soil from when you plant them to about 3 weeks before you harvest them for best results. Do it every month or so as a “treat” for your broccoli plants and you will not regret it!
5: Peppers (Caspicum annuum)
A small plant of bell peppers will produce massive fruits compared to its size: give it some coffee grounds to help it in this effort!
These Sun loving vegetables too work miracles, really! In the time span of a season they will grow from tiny plants with two leaves to adults with hard stems and amazing fruits.
Peppers, of course eat a lot too. So, give them regular sprinklings of used coffee grounds. Start just after you have planted them. Then repeat monthly and keep going all through the fruiting season, which is quite long indeed!
6: Rhubarb (Rheum rhabarbarum)
Rhubarb is a super vegetable which likes a “cup of coffee”, well in powder for, too. It is extremely rich in vitamins, but unlike other plants, it packs them in its famously red stalks.
It is very common in sweets, but do you know it is also excellent for you mouth and gums? Its tincture, in fact, is used to cure mouth ulcers.
Rhubarb us very string and vigorous, no wonder it likes some energy boosts every now and then. Start sprinkling a bit of used coffee when you plant it and repeat every three to four weeks till harvest time.
Then, always reward it with some used coffee grounds when you pick stalks and it will grow new ones.
Friut Plants That Like Coffee Grounds
You will get the best results with coffee grounds if you use them with acid loving small shrubs. Blueberries and raspberries are the sort of plants that will respond well to coffee grounds, rather than bigger trees, like apples or plums.
These are also vitamin rich berries, and they need a lot of energy to produce their often long and generous harvest. And here are some of the best.
1: Blueberry (Vaccinium spp. or Cyanococcus spp.)
You know that blueberries are super rich in vitamins, so, help them with some coffee grounds to fill their juicy berries with them!
They are also acid loving plants, which by now you know that means that they will like fresh, unused coffee grounds too.
Blueberry plants will last you for years. Give them some coffee grounds in spring, when they start the vegetative phase, then again as soon as they fruit and once more when the berries are ripening. That coffee will add to the juiciness and freshness of the dark berries!
2: Cranberries (Vaccinium oxycoccus)
Cranberries too are very vitamin rich berries, and they too like coffee grounds, fresh or used. Cranberries, with their Christmas red color, are a real delicacy.
They are more rare and harder to find than blueberries, but they are actually very closely related, and they like similar conditions.
Make sure you give your cranberries some coffee grounds when spring comes; then keep sprinkling the soil at regular intervals, before the harvest season and all through it!
3: Raspberry (Rubus idaeus)
Raspberries are lovely and nutritious, and you can use coffee grounds to help them grow and ripen. They have that very acidic flavor which alone should suggest that they love coffee.
And in fact, this generous shrub can do with a little help every now and then, and the ready nutrients of coffee grounds are perfect!
Give used coffee grounds to your raspberries in spring and then all through the fruiting season, till they go dormant. You can also give them unused coffee grounds, but don’t overdo it.
However, these are ideal if the soil is alkaline. Raspberries like it on the acidic side, but not as much as blueberries or cranberries.
Houseplants That Like Coffee Grounds
Looking at the plants we grow indoors, some will enjoy a sprinkling of coffee grounds too. Actually quite a few of them do, and we have chosen the most “appreciative ones”.
Be careful though! A pot or container is a very limited space and ecosystem: use very little quantities if you really love your houseplants.
1: African Violet (Saintpaulia ionanthia)
African violets are so sweet, with their fleshy leaves and vibrant flowers! And let me tell you, it’s not easy to keep in such good shape when you live in a small pot.
It gets even worse because these plants look like they are “out of time”; so we forget them. Instead, they need lots of energy and nutrients…
Do give a little sparing sprinkle of used coffee grounds to your African violets, especially if you see they are lacking energy and vitality. They will rally appreciate it and they will perk up as fast as possible.
2: Christmas Cactus (Schlumbergera spp.)
How many flowers do you get from a Christmas cactus? Loads, really. And do you think it can do all that without a little help from you? No! Then make sure it gets all the nutrients it needs to come back year after year with those brightly colored flowers…
A little sprinkle of used coffee grounds before Christmas cactus blossoms will go a long way to helping your Christmas cactus give its best.
You can also give it some extra boost with a gentle sprinkling when it comes out of dormancy and produces new “leaves” (or “segments’ as they are called properly).
3: Jade Plant (Crassula ovata)
Jade plant is like a natural jewel, with its green (or yellow) leaves that look like stones. It has a very “Japanese” look and you may imagine it next to a tea ceremony.
But no… it prefers coffee instead! Coffee grounds will help Jade plant, especially if you want your plant to bloom regularly.
To do so, just add a modest quantity of coffee grounds to the potting mix every six months or every year. That will be enough to guarantee regular and vigorous blooms.
4: Peace Lily (Spatiphyllum spp.)
An all tine favorite houseplant, peace lily can get extra shine to glossy leaves and some extra boost for its candid blooms with a bit of coffee… grounds of course!
This very vigorous and fresh looking plant in fact will appreciate the love and extra nutrients you give her with some pf your used coffee…
The high nitrogen levels of coffee grounds are in fact really good for its leaves and growth. So, give some used coffee grounds to your peace lily when it comes out of dormancy and as soon as you see that it is starting to bloom.
5: Philodendron (Philodendron spp.)
Maybe the most popular houseplants on the planet, philodendrons come in many shapes, sized and colors. But they all have impressive, large, beautifully shaped and glossy leaves.
No wonder they like to eat quite a lot too. And as we said the hugh nitrogen content of coffee grounds is excellent for leaf growth.
Be quite regular with philodendrons; give them a modest but regular dose of used coffee grounds. Ideally, once a month all through the year, apart when they are dormant. You will see that the foliage of your philodendron will improve.
Coffee Time For Your Plants !
Garden plants and houseplants, vegetable and fruiting shrubs… All these and other plants can benefit from coffee grounds used well.
Now you know how to. Now you know which plants like them most, don’t let me catch you throw them away from now on..
Updated on by Amber Noyes
Amber Noyes born and raised in a suburb Nebraska town, San Mateo. She holds a master’s degree in horticulture from University of California as well as an BS in Biology City College of San Francisco. With experience working on an organic farm, water conservation research, farmers markets, and potted plants she understands what makes plants thrive and how can we better understand the connection between microclimate and plant health. When she’s not on the land, Amber loves informing people of new ideas/things related to gardening, especially Indoor gardening, houseplants and Growing plants in a small space.