- Using Coffee Grounds in the Garden
- The problem of coffee waste
- Potential for coffee grounds to improve soil and plant growth properties
- The experiment
- The Results
- What explains this decreased plant growth?
- Should I add coffee grounds to my garden?
- Using Coffee Grounds Correctly
- Garden Myths – Learn the truth about gardening
- Coffee Grounds in Garden
- Coffee Grounds Acidify Soil
- Coffee Grounds Make a Good Mulch
- Coffee Grounds are a Good Source of Nutrients
- Coffee Grounds make Plants Grow Better
- Coffee Grounds Prevent Weeds
- Coffee Grounds Repel Cats
- Coffee Grounds Kill Slugs
- Coffee Grounds Change the Color of Hydrangea
- Coffee Grounds get rid of Ants
- Coffee Grounds Kill Insects
- Coffee Grounds Suppress Fungal Diseases
- Goodbye Cellulite
- The Benefits of Coffee Grounds
- Where to Get Coffee Grounds
- There’s No Use Crying Over Spilled Coffee Grounds
- Coffee Grounds Contain Optimum Plant Nutrition
- How To Use Coffee Grounds In The Garden
- Feed Your Lawn With Coffee Grounds
- Keep Pests Out Of Your Garden & Attract Beneficial Creatures
- Your Yard & Garden Will Be A Delight For The Senses
- What If You Don’t Have Enough Coffee Grounds Garden Tip?
- How Do You Begin?
- Related posts:
Using Coffee Grounds in the Garden
Spent coffee grounds are increasingly recommended by professionals and gardeners as a sustainable way to improve your garden soil and provide nutrients to your plants. Claims include improved soil structure, an ideal carbon to nitrogen ratio, improved fertility and provision of nitrogen1. However, the scientific literature has not sufficiently assessed the impacts on soil and plant production.
Recent research conducted by Dr Stephen Livesley and Sarah Hardgrove from the University of Melbourne, has shown that fresh (uncomposted) spent coffee grounds, applied directly to gardens, can significantly decrease plant growth and development. This article reviews the case for using spent coffee in the garden and describes recent scientific findings and their implications.
The problem of coffee waste
An estimated 6 million tons of spent coffee ground waste is produced annually worldwide2, predominantly in cities. Australia’s contribution is estimated at 75,000 tonnes annually, and with coffee consumption rates in Australia increasing at a rate of 4.3% per year, the volume of waste is also set to increase. Using spent coffee grounds as an urban soil amendment provides an attractive and sustainable way to take advantage of this under-utilised urban waste product.
Potential for coffee grounds to improve soil and plant growth properties
Spent coffee grounds can possibly provide similar plant growth and soil property benefits as other organic amendments such as manures, biochar, vermicasts and compost. These amendments provide nutrients (particularly nitrogen), increase plant growth, improve soil water and nutrient holding capacities, improve soil structure and water infiltration, increase buffering capacity against leaching of nitrates and changes in pH, increase biological activity and resilience against pathogens3.
Under natural conditions, plants have adapted and evolved to the soil and climatic conditions of their local environment. As the soil properties and nutrient content varies, so too will plants vary in their nitrogen requirements and pH preferences for optimal growth. These differences affect our decisions about application rates of fertiliser for various crops. In addition, soil texture affects the movement of water and nutrients throughout the soil and their availability to plant roots. The aim of this recent research was to investigate the impacts on plants that vary in their nutrient requirements and pH preferences.
In a greenhouse pot trial, broccoli, radish, leek, viola and sunflower (chosen for their varied nutrient-pH preferences) were grown in sand, loam and sandy clay loam substrates. Four treatments were applied: no treatment control, spent coffee grounds (5% volume), fertiliser and spent coffee grounds plus fertiliser.
Concurrently, a field trial grew the same plants under six treatments: control, fertiliser, and spent coffee grounds at 2.5%, 5%, 10% and 20% volume application rates (in the upper 10cm of soil).
In the greenhouse trial, all plants grown in coffee-amended soil treatments showed poor growth compared to the control and fertiliser-amended soil treatments. The left hand picture below shows the five plants under the four treatments, from top to bottom: control, fertiliser; spent coffee grounds; spent coffee grounds plus fertiliser.
Water holding capacity
The results for the greenhouse trial showed a general trend for increased water holding capacity for poorly structured soils, but less of an impact for well-structured soils. The results also suggested that these improvements take time to emerge. Other research also shows that benefits do not clearly emerge until 6-12 months after application, depending on species, soil type and temperature4.
The pH of the soil was also tested to investigate whether the acidic nature of spent coffee grounds may be impacting plant growth. In the field trial, the pH of the soil amended with spent coffee grounds was similar to the pH amended with fertiliser. As such, pH from the added coffee could not adequately explain the plant growth response.
What explains this decreased plant growth?
The two possible explanations for this plant growth response were biological nitrogen immobilisation (nitrogen drawdown) and phytotoxicity.
Nitrogen drawdown occurs when the amount of nitrogen required by decomposer microorganisms is higher than the amount of nitrogen that is available for plants from the soil. As organic matter decomposes, nitrogen is supplied to the plants via its roots from the surrounding soil water solution. However, the vast majority of the nitrogen in soils is not readily available to plants. In order for it to become available, it needs to be transformed by microorganisms within the soil water solution, a process known as mineralisation. Through mineralisation, organic nitrogen changes to inorganic nitrogen and becomes plant available. In its plant available form, as nitrate (NO3-) and ammonium (NH4+), it can be easily translocated throughout the plant and soil.
Conversely, as microorganisms require nitrogen as fuel for their own metabolic processes, they can also draw it out of the soil water solution, leaving the soil apparently deficient in nitrogen and, therefore, unavailable for plant uptake: a process known as biological immobilisation. These processes can operate dynamically as the chemical nature of the soil changes over time and new material is added. The carbon to nitrogen (C/N) ratio is a useful guide here, as an organic amendment with a higher C/N ratio will mineralise more slowly than one with a low C/N ratio and is more likely to lead to biological immobilisation as nitrogen is taken up by the microbes involved in decomposing the new large, carbon substrate pool. The C/N ratio of the coffee in this research was 23. It is generally accepted than a C/N ratio occurring within the range of 20-30 will not lead to microbial immobilisation5.
A mineralisation study was also conducted as part of this research to test whether the plant growth differences were the result of nitrogen drawdown. The findings clearly showed that the nitrogen drawdown could not explain the plant growth response.
The most likely explanation for decreased plant growth is a toxic stress response as a result of the applied coffee grounds. The exact mechanism of phytotoxicity remains unclear, however caffeine, tannins, polyphenols and lignin content have all been implied in previous scientific research.
Should I add coffee grounds to my garden?
This research suggests that when fresh, uncomposted coffee is added to gardens at volume application rates of 2.5% and higher it will likely decrease all plant growth and development. As such, it is probably a better idea to add coffee grounds to your compost to allow for decomposition of toxic components, and for the improved water holding capacity benefits to emerge. It is recommended that no more than 20% volume of spent coffee grounds be added to your compost6.
Alternatively, if you have a patch that is lying fallow for 6 months or more and you want to reduce the rate of weed growth, then fresh spent coffee grounds incorporated into the soil or applied as a thin layer of mulch, is a pretty good idea!
Sarah Hardgrove is completing the final semester of the Master of Urban Horticulture at the University of Melbourne’s Burnley campus.She also works part time at a garden centre in Melbourne.
Photos: Experiment results: Sarah Hardgrove. Other: Sharron Pfueller
Using Coffee Grounds Correctly
- —Ken; just outside of Philadelphia, PA.
I am spreading coffee grounds from the local Bagelsmith under my five-year old pines and spruces with the idea that it will acidify my lousy clay soil. Based on a number of enthusiastic ‘testimonials’ on a recycling website I have spread several bushels of grounds so far. Am I deluded? Worse, am I doing harm?
- —Richard at Rutgers University, New Jersey
Mike: I live in a part of the world that’s so young geologically it was recently covered with glaciers. There isn’t much soil, so I make a lot of compost. Besides the usual stuff (kitchen scraps, newspaper and cardboard), I can receive 30 pounds of grounds a week from the only coffee shop on Prince of Wales Island…
- —Jay in Craig, Alaska
Answer. First, a few extraneous words to Craig up in Alaska: I know that many uninformed sources advise using shredded newspapers and cardboard as the ‘dry browns’ in a compost pile, but: 1) newspaper ink is more toxic than these people realize; 2) newsprint is bleached, creating cancer-causing dioxins; and 3) cardboard contains nasty glues and other chemical ‘fillers’. More importantly, these things contain zero nutrition for your plants. If you don’t have enough leaves, experiment with wood shavings or sawdust. They can be difficult to compost, but are far superior to heavily processed paper products.
Now, on to coffee grounds! When we first started doing this show, we warned people to only spread coffee grounds around acid-loving plants, like azaleas, rhododendrons and blueberries, because the grounds were bound to be acidic; and not to overdo it on those and other flowering plants, as the grounds were certainly high in Nitrogen, which makes plants grow big, but can inhibit the numbers of flowers and fruits.
But then we were sent some test results that showed grounds to be neutral on the pH scale! To find out what gives, I called Will Brinton, founder and Director of the Wood’s End Research Laboratory in Maine, the definitive testers of soils, composts, and raw ingredients used in large-scale composting. Will solved the mystery instantly. Woods End, it turned out, was the source of that neutral test! Ah, but some follow-up investigation later revealed that it hadn’t been coffee grounds alone, as the person submitting the material for testing had stated, but grounds mixed with raw yard waste, the classic ‘dry brown’ material that is the heart of a good compost pile.
READ COMPLETE ANSWER
It turns out, as expected, that “coffee grounds alone are highly acidic,” says Will, who saved all the grounds from his Lab’s break room for a week recently just to test for us (“Eight o’ Clock” coffee, which I remember fondly from our old A & P neighborhood supermarket). They came out at 5.1, a perfect low-end pH for plants like blueberries that thrive in very acidic soil. “But that’s the most gentle result we’ve ever found,” Will quickly added, explaining that the other 31 samples of raw coffee grounds they’ve tested over the years all had a pH below 5, too acidic for even some of the so-called acid loving plants.
“And in some ways, the grounds are even more acidic than those numbers imply”, adds Will, who explains that the coffee grounds they’ve tested have also had a very high residual acidity; so high he recommends adding a cup of agricultural lime to every ten pounds of grounds BEFORE you add them to your compost pile. (High-quality hardwood ashes could be used instead of the lime, and would add more nutrients to the mix than the lime would.)
But I had to quickly sputter that I never recommend adding anything to raw ingredients before composting for fear of upsetting the apple—eh, compost—cart. “Neither do I,” said Will; “this is a unique situation.”
And he certainly doesn’t think grounds should be used in their raw form. First, he explains, they are so acidic and so Nitrogen rich that you risk creating a ‘mold bloom’ where you spread them. And second? “There’s no life in those grounds; its all been boiled or perked away.” Instead, he suggests doing what the guy with that original sample did—adding the grounds to microbe-rich yard waste and composting that perfect combination. Will liked my suggestion of four parts shredded leaves to one part grounds by weight, but adds that even having grounds make up 10% of a pile of otherwise shredded leaves would create great compost.
Nutrient content? Will explains that the kind of coffee grounds a typical homeowner would produce or obtain are around 1.5% Nitrogen. There’s also a lot of Magnesium and Potassium, both of which plants really like; but not a lot of phosphorus (the “fruiting and flowering nutrient”) or calcium, a mineral that many plants crave, and whose lack helps explain that recalcitrant acidity. (“Lime” is essentially calcium carbonate, and wood ashes are also very high in calcium; click HERE for a previous Question of the Week that goes into great wood ash detail.)
So mix those coffee grounds in with some lime or wood ash and then into lots of shredded leaves; you’ll make a fine, high-quality compost. The only exception I can think of is our listeners out West cursed with highly alkaline soil; you could try tilling in some grounds alone and see if it moves your nasty soil towards neutral with no ill effects.
Otherwise, we can’t recommend their raw use; the acidity could be high enough to damage even acid-loving plants. And yes, this means that our poor New Jersey listener could be harming his plants with all that uncomposted coffee. Unfortunately for him, Northeast soils are ALREADY acidic; that’s why many homeowners in the North lime their lawns. And when I scrolled through those ‘testimonials’ that so swayed him, I noticed that they all seemed to be from California, where the soils are highly alkaline. And you can’t improve clay soil by making it more acidic or alkaline; the only way to REALLY improve clay soil is to dig it up and toss it into the woods!.
For lots more info about high quality testing of soils, composts and raw ingredients, visit the Wood’s End web site: www.woodsend.org
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Garden Myths – Learn the truth about gardening
Coffee Grounds have a reputation for solving all kinds of garden problems. It is claimed that they reduce the number of diseases, ward off insects, fertilize the soil, and even keep slugs from eating your plants. Let’s have a look at the truth behind coffee grounds.
Free coffee grounds for your garden
Coffee Grounds in Garden
Coffee has become a very popular drink, and the process of making coffee results in something called coffee grounds. It is the solid dark brown material left over after making coffee. Households produce small quantities of the stuff, and if you want more, many coffee houses will gladly give gardeners their grounds. After all, it is just garbage to them.
Since grounds are free and organic, they have generated a lot of myths for gardeners.
The following is a list of the benefits ascribed to coffee grounds.
Coffee Grounds Acidify Soil
I have discussed this in more depth in Coffee Grounds Acidify Soil. The short answer is that coffee grounds are only slightly acidic, and in the long term they will not acidify soil. It is pure myth.
Coffee Grounds Make a Good Mulch
Coffee Grounds are organic, and will slowly decompose in the garden–sounds like a good mulch. Coffee grounds are quite fine, and as such they compact easily. Anything that compacts will reduce the amount of water/rain and air reaching the soil. This is not good for your plants or the other soil biota.
Grounds can be added, in small amounts, to other mulch and it will work just fine. Just don’t use it as the only mulch. A sprinkling of grounds on the soil here and there is fine.
As indicated in Coffee Grounds Acidify Soil, there is evidence that uncomposted coffee grounds inhibit the growth of some plants and affect the germination of seeds. It is probably a good idea to compost the grounds before adding them to your soil.
Coffee Grounds are a Good Source of Nutrients
Coffee grounds contain 1-2% nitrogen, 0.3% phosphorous and 0.3% potassium along with a variety of micronutrients. The amounts of P and K reported seem quite variable, but there are low amounts of both of them. These nutrients are tied up in large molecules similar to other types of organic material as discussed in more detail in Organic Fertilizer – What is its Real Value.
Coffee grounds, either in the soil or in your compost bin, will slowly decompose releasing the nutrients. Just like any other organic material, this is a good slow release fertilizer. Don’t expect quick results from this fertilizer, but over time it will provide nutrients for your plants.
Coffee Grounds make Plants Grow Better
That is kind of a big statement without any specific claims. It is hard to argue against such a statement.
As mulch, it certainly benefits plants—any mulch will do that. It is a slow release fertilizer and that is always good for plants.
The grounds also contain a variety of specific chemicals that have been shown to enhance the growth of seedlings in the lab. However, it has also been shown that the grounds inhibit the growth of certain types of seedlings, including tomatoes. These are all lab results using seedlings—not mature plants. It is unclear if any of these observations translate to the garden situation. Nor is it clear what effect these chemicals have on mature plants.
Because of the potential problem of these chemicals, it is probably best to compost coffee grounds before you add them to your soil. It is also a good idea to keep them away from seedlings.
Coffee Grounds Prevent Weeds
I have not been able to find any confirmation of this. Certainly, as mulch, it will reduce the number of weeds—any mulch will do that. It is possible that the chemicals in coffee grounds inhibit some weed seedlings in the same way that they inhibit tomato seedlings, but that is just a guess on my part.
Since coffee grounds also help plants to grow, you can expect that there will be some weeds that will grow better after being treated with the grounds. After all, weeds are just plants. If you believe that coffee grounds make plants grow better, then you have to believe that they will also make weeds grow better.
Coffee Grounds Repel Cats
I found this statement on some sites, but can’t confirm it or deny it.
Coffee Grounds Kill Slugs
Since slugs seem to be a big problem in the garden, I have made two previous posts; Do Beer Traps Kill Slugs, and Does Copper Repel Slugs. So what about coffee grounds?
Studies have shown that caffeine will kill slugs and snails. Spraying plants with caffeine will deter slugs from eating the plant. These findings have probably been misinterpreted and translated into the fact that coffee grounds also kill or deter, slugs and snails. This type of extrapolation happens a lot and causes many of the myths discussed at GarenMyths. The caffeine that was sprayed on plants was fairly concentrated compared to the caffeine found in grounds, which have very little caffeine. In fact, the concentration of caffeine in grounds is so low, it won’t kill slugs or snails.
I have found no evidence of other types of chemicals in coffee grounds that would kill slugs–this is a myth.
Will coffee grounds deter slugs from reaching a plant? Do they dislike crawling over the grounds so much that they leave your plants alone? So far I have found no scientific data that suggests this is true, and unlike the videos for beer and copper, no one has made a video showing that slugs hate to crawl on coffee grounds.
To resolve this more clearly I decided to run a test, the results of which are reported in Slugs and Coffee Grounds. It clearly shows that slugs don’t mind crawling on coffee grounds.
Coffee Grounds Change the Color of Hydrangea
Some hydrangea have pink flowers in alkaline soil and blue flowers in acidic soil. Since blue is the color preferred by most gardeners, it has been recommended that coffee grounds added to soil will make hydrangea blue. As discussed above, coffee grounds will not change the soil pH, so they will not change the color of hydrangea flowers.
Coffee Grounds get rid of Ants
Apparently, ants do not like the smell of coffee grounds and they will avoid them. It is claimed that if coffee grounds are put onto an ant hill, they will leave the area.
This seems easy enough to test, so I decided to run some tests in Ants and Coffee Grounds.
Coffee Grounds Kill Insects
Lots of web sites talk about coffee grounds acting like an insecticide, but they give few details. Most talk about caffeine as the insecticide, and that has some truth if it is used in high enough concentrations–much higher than what is found in grounds.
How would you use grounds as an insecticide? Spray it on the leaves? It is a solid material consisting of fairly large particles. It is not practical to use it on plants for flying insects. What about soil insects? People feed it to dew worms and they don’t get killed.
There does not seem to be any evidence that coffee grounds work as an insecticide.
Coffee Grounds Suppress Fungal Diseases
I found this stated in quite a few places. Here is a quote from one source, “The natural mold and fungus colonies on coffee appear to suppress some common fungal rots and wilts, including Fusarium, Pythium, and Sclerotinia species,”. Interestingly, the underlined section of the quote was attributed to a report written by Dr. Linda Chalker-Scott, someone I greatly admire and trust. So this has to be true—right?
First of all molds are fungi—they are not two separate things as stated in the quote. Secondly, the quote from Dr. Chalker-Scott dealt with coffee grounds, not coffee. These might seem like small errors but in my experience they usually indicate an author who misinterprets information–it is starting to smell like a myth!
What Dr. Chalker-Scott said was (ref 3) “ Researchers suggest that bacterial and fungal species on decomposing coffee grounds, prevent pathogenic fungi from establishing”. The words, “researchers suggest” are interpreted as a “known fact”–coffee grounds suppress fungal diseases. You have just witnessed the birth of a myth.
Dr. Chalker-Scott goes on to say that this work was all done in the lab under controlled conditions and that “their efficacy in gardens and landscapes is unknown”. What that means is that there is no scientific evidence that coffee grounds suppress fungal diseases in the garden. Many things scientists see in the lab, under controlled conditions do NOT translate into the garden.
There seems to be no clear evidence that coffee grounds suppress fungal diseases in plants.
I quote, “some celebrities swear by this odd treatment involving old coffee grounds: Mix an egg white with the day’s used coffee grounds, warm it up in the microwave, and then spread the gooey concoction on your problem areas. Wrap tightly in saran wrap. Boom—you’ve just saved $700 at the spa.”
If it works for celebrities it has got to work. Give it a try, and post before and after pictures 🙂
2) Coffee Grounds and Composting: http://extension.oregonstate.edu/lane/sites/default/files/documents/cffee07.pdf
3) No longer available
4) Do Coffee Grounds Really Kill Slugs: http://www.paghat.com/coffeeslugs.html
5) Slugs in Gardens: http://www.jstor.org/discover/10.2307/1386?uid=3739448&uid=2&uid=3737720&uid=4&sid=21104488656997
6) Photo Source: Tristan Ferne
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Ask Mr. Burger – Can used coffee grounds be beneficial for my garden or lawn?
This question typically comes up this time of year when people are looking for ways to feed their plants more organically and be environmentally friendly. While we can’t say for sure how much benefit you actually get from the grounds; we can say that they offer some benefits to your garden and your lawn. We’ve included a couple articles on using coffee grounds by Amy Grant and Heather Rhoades for your reference.
Coffee Grounds As Lawn Fertilizer – How To Apply Coffee Grounds On Lawn
By Amy Grant
Just as the aroma and caffeine of a cup of Joe in the morning stimulates many of us, using coffee ground on grass can also stimulate healthier turf. It isn’t the caffeine that stimulates healthy grass growth, but rather the nitrogen, phosphorus and trace minerals that coffee grounds contain. These nutrients are released slowly, which is a big benefit over quick release synthetic fertilizers. The nutrients in coffee grounds are slowly broken down, allowing the turf to have a longer period of time to absorb them ensuring stronger turf for longer.
Using coffee grounds as lawn fertilizer is also good for the worms. They love coffee almost as much as we do. The earthworms eat the grounds and in return aerate the lawn with their castings, which breaks up the soil (aerates) and facilitates beneficial microbial activity, further stimulating lawn growth.
Improper synthetic fertilizer applications often result in lawn burn as well as contaminating our water via ground run off. Using coffee grounds as lawn fertilizer is an eco-friendly method for nourishing the lawn and it can be free or darn near so.
How to Apply Coffee Grounds on Lawns
When using coffee grounds on the grass you can save your own or hit up one of the multitude of coffee houses. Starbucks does indeed offer grounds gratis, but I am sure smaller coffee shops would be more than willing to save the grounds for you as well.
So how do you go about feeding lawns with coffee grounds? You can be super lazy and simply throw the grounds out onto the lawn and let the earthworms dig it into the soil. Don’t let the grounds completely cover up grass sprigs. Rake or sweep it out lightly so there aren’t any deep piles atop the grass. You can also use a bucket with holes punched through the bottom or a spreader to broadcast the grounds. Voila, can’t get much simpler than that. Reapply the coffee ground lawn fertilizer every month or two thereafter to promote a thick, green turf.
Composting With Coffee Grounds – Used Coffee Grounds For Gardening
By Heather Rhoades
Whether you make your cup of coffee daily or you have noticed your local coffee house has started to put out bags of used coffee, you may be wondering about composting with coffee grounds. Are coffee grounds as fertilizer a good idea? And how do coffee grounds used for gardens help or hurt?
Composting Coffee Grounds
Composting with coffee is a great way to make use of something that would otherwise end up taking up space in a landfill. Composting coffee grounds helps to add nitrogen to your compost pile. Composting coffee grounds is as easy as throwing the used coffee grounds onto your compost pile. Used coffee filters can be composted as well. If you will be adding used coffee grounds to your compost pile, keep in mind that they are considered green compost material and will need to be balanced with the addition of some brown compost material.
Coffee Grounds as Fertilizer
Used coffee grounds for gardening does not end with compost. Many people choose to place coffee grounds straight onto the soil and use it as a fertilizer. The thing to keep in mind is while coffee grounds add nitrogen to your compost, they will not immediately add nitrogen to your soil. The benefit of using coffee grounds as a fertilizer is that it adds organic material to the soil, which improves drainage, water retention and aeration in the soil. The used coffee grounds will also help microorganisms beneficial to plant growth thrive as well as attract earthworms.
Many people feel that coffee grounds lower the pH (or raise the acid level) of soil, which is good for acid loving plants. But this is only true for unwashed coffee grounds. “Fresh coffee grounds are acidic. Used coffee grounds are neutral.” If you rinse your used coffee grounds, they will have a near neutral pH of 6.5 and will not affect the acid levels of the soil.
To use coffee grounds as fertilizer, work the coffee grounds into the soil around your plants. Leftover diluted coffee works well like this too.
Coffee grounds can also be used in your garden for other things –
- Many gardeners like to use used coffee grounds as a mulch for their plants.
- Other used for coffee grounds include using it to keep slugs and snails away from plants. The theory is that the caffeine in the coffee grounds negatively affects these pests and so they avoid soil where the coffee grounds are found.
- Some people also claim that coffee grounds on the soil is a cat repellent and will keep cats from using your flower and veggie beds as a litter box.
- You can also use coffee grounds as worm food if you do vermicomposting with a worm bin. Worms are very fond of coffee grounds.
Using Fresh Coffee Grounds
We get lots of questions about using fresh coffee grounds in the garden. While it’s not always recommended, it shouldn’t be a problem in some situations.
- For instance, you can sprinkle fresh coffee grounds around acid-loving plants like azaleas, hydrangeas, blueberries, and lilies. Many vegetables like slightly acidic soil, but tomatoes typically don’t respond well to the addition of coffee grounds. Root crops, like radishes and carrots, on the other hand, respond favorably – especially when mixed with the soil at planting time.
- The use of fresh coffee grounds are thought to suppress weeds too, having some allelopathic properties, of which adversely affects tomato plants. Another reason why it should be used with care. That being said, some fungal pathogens may be suppressed as well.
- Sprinkling dry, fresh grounds around plants (and on top of soil) helps deter some pests same as with used coffee grounds. While it doesn’t fully eliminate them, it does seem to help with keeping cats, rabbits and slugs at bay, minimizing their damage in the garden. As previously mentioned, this is thought to be due to the caffeine content.
- In lieu of the caffeine found in fresh, unbrewed coffee grounds, which can have an adverse effect on plants, you may want to used decaffeinated coffee or only apply fresh grounds minimally to avoid any issues.
Coffee grounds and gardening go together naturally. Whether you are composting with coffee grounds or using used coffee grounds around the yard, you will find that coffee can give your garden as much of a pick me up as it does for you.
Check out the website, “Gardening Know How” at https://www.gardeningknowhow.com for additional information on this topic and others concerning your lawn and garden.
Is your yard yellow or patchy in places? Does it lack the zest and appeal of your neighbor’s? A cup o’ joe might just wake up your lagging lawn.
Coffee grounds are organic matter that add nutrients to the soil. They act as any fertilizer, amending dirt with essential components that tend to blanch through winter storms or annual growth cycles. Enrich alfalfa or rabbit tea with coffee grounds to compliment and maintain proper pH.
As with any ground shells or hulls, java beans can be worked into soil to improve aeration and drainage. This is especially effective on neglected, scalped or compacted clay soil.
Ground espresso beans will also help loosen the soil, thereby promoting improved absorbency of air, water and nutrients. They should not, however, be used as mulch because they are so fine and can blow away or impede absorption. Coffee grounds, on the other hand, make great mulch. Gardeners report trees, shrubs and flowers responding very well when mulched with coffee grounds.
Free sources of coffee grounds are right under your nose. Recycle your own by adding the grounds to your compost bin. You can also save them in your garage until you get a large garbage can full, enough to cover your whole lawn.
Starbucks coffee shops usually offer their left-overs free for the taking. This is part of their corporate recycling program. Standard protocol has them empty their grounds into white trash bags behind the counter during the day. In the evenings, these are normally combined in a single bin at the back of the store.
Gardeners can ask for the white bags any time of the day – although people are not encouraged to interrupt busy sales times – and carry them slung over their shoulders right out the door. Espresso beans are specially packaged and offered near the entrance ways, also for free.
While coffee houses handle their waste in various ways, one thing remains constant—they all need to dispose of grounds. If your local espresso shop isn’t recycling this valuable organic material, guilt-trip them into allowing you to place a new collection bin behind their counter for that purpose. No extra effort is required of their employees. Owners will be recycling and can then advertise that they are environmentally friendly. Also, they’ll have less garbage to pay for.
Fill to the Brim
Standard fertilizer distribution can be used with coffee grounds. A spread rate of one cubic yard per 1,000 square feet of lawn is sufficient, although common practice varies. It can be applied in a very thin layer or more thickly, as you see fit.
While it’s very difficult to apply too much, don’t layer it on so thick that grass is covered or water is repelled. That will encourage a mushroom bloom that could become annoying. Also, earthworms go crazy for coffee grounds. Some people think they even become addicted to coffee for the same reasons people do. Worms tear through coffee grounds like any compost. They will eat through the equivalent of their own body weight every 24 hours. They are nature’s roto-tiller.
Worm castings are considered one of the best soil amendments in the world. Where there is an abundance of worms, however, there is likely to also be gophers to feed on the slimy bistro. Gophers are a natural part of a healthy ecosystem, but they are not usually welcome under your front lawn. If you’re working toward greater greens, make sure you plan ahead for handling the boom in gopher population that could follow.
Good to the Last Crop
Coffee grounds can be applied directly to the base of shrubs and trees, or worked into the top layers of flower and garden beds. When it comes to the lawn, homeowners quickly adopt personalized methods of spreading the crushed seed pods on their grass.
You might like the pile-and-sling method. Empty bags of coffee grounds in piles around your lawn. Grab shovels full and sling the seeds to all corners of your grass. You can also cut large holes around the base of a five-gallon bucket. Fill the bucket with the grounds. Twist and turn your wrists much like you would for spreading seed or chemical fertilizer.
Once the coffee grounds are spread over your grass, you can brush them in using a push-broom. You can also water the treated area. Don’t let coffee grounds cover up sprigs of grass since your lawn must see the light to remain green and plush.
For about a week after application, you will enjoy the energizing aroma of coffee in the heat of the day. Soon after, you’ll probably notice the color of your lawn deepen to a rich hunter green as the grass soaks up the breakfast brew. Reapply coffee grounds every month or two to your lawn or any plant that needs a pick-me-up.
Having a great looking lawn depends on ensuring your grass plants get the nutrients and water they need to develop strong root systems, so they can withstand drought and battle insects and fungal infestations. But sometimes, getting all the nutrients your lawn need can become an expensive endeavor. That’s when it’s time to look for alternatives to pricey store-bought fertilizers that can enable you to feed your lawn without deleting your bank account.
If you’re lucky enough to live near a horse or dairy farm and you have the space to compost manure without drawing the wrath of every neighbor within a block radius, good for you; but for most of us, we need to find other ways of keeping our lawns green and healthy.
The Benefits of Coffee Grounds
Fortunately, most of us have access to one waste product that not only feeds our grass, but it also smells good while it’s doing it. That “miracle” product is, as the title says, coffee grounds, and it can provide your lawn and your other plants with much-needed nutrients and other important benefits. For instance, coffee grounds:
- are a good source of compostable nitrogen, which is vital for lawn health;
- are close to pH neutral, which means they won’t burn your grass plants like some other forms of natural nitrogen;
- repel slugs and snails without the need for poisonous pesticides, so you have fewer pests to worry about;
- improve the structure of soil, especially in heavy or clayey soils, for better, deeper root development.
Plus, they’re easy to apply: Simply apply them directly to the soil, ideally before aerating, so they mix in. Coffee grounds help microorganisms break down the soil so nutrients are more available for plant use, but to do that, they need a boost of nitrogen; consider applying nitrogen at the same time as you apply your coffee grounds to ensure your plants and your helpful microorganisms are competing for the same source of nitrogen. You can store your extra coffee grounds in a plastic trash can or throw them on your compost pile or work them into the soil around your other plants along with a boost of nitrogen-based fertilizer.
Where to Get Coffee Grounds
Now you know how to use them – where do you get them? Well, you could haunt your friends and neighbors, but that would be about as popular as the idea of using cow manure to fertilize your lawn. Instead, ask your local coffee shop if you can have their spent grounds. Most coffee shops are happy to have someone take them, especially if you’re a loyal customer. Restaurants can be another option, but most restaurants are too busy and diversified to be bothered with setting aside their grounds.
Of course, feeding is just one part of having a great-looking lawn. Keeping it properly watered is also critical, and having an up-to-date sprinkler system is the best way to do it. At Garden Irrigation, we offer the most advanced sprinklers and components to help New Jersey residents keep their lawns green no matter what Mother Nature brings our way. To learn more about the sprinkler system options we offer and how sprinklers can help you keep your New Jersey lawn green and healthy, give us a call at 1-800-WET LAWN or Contact Us today.
If you love gardening and drinking great coffee, you will be happy to learn that coffee grounds make a great tonic for garden plants and grass.
In this article, we will explain why coffee grounds are so good for the soil in your yard. We’ll also share some smart tips on how to use coffee grounds in the garden.
There’s No Use Crying Over Spilled Coffee Grounds
If you’ve just been tossing your spent coffee grounds in the trash, don’t waste time kicking yourself over it. There’s no time like the present to begin a great new habit.
Set up a simple, plastic compost pail with a lid in your kitchen or porch. Put your coffee grounds, fruit and veggie trimmings in the pail and add them to your compost heap every day.
If you are new to composting, you will soon learn that it is a great way to feed the soil in your yard and garden.
There are some who never need to buy any kind of plant food because good soil feeds plants naturally. Coffee grounds are a great addition to your compost pile, heap or bin.
They are also a good amendment dispersed directly into the garden soil. They contain a tremendous amount of nutrients that are readily absorbed.
Coffee Grounds Contain Optimum Plant Nutrition
One recent study was conducted using coffee grounds from Starbucks. The researchers found that Starbucks’ coffee grounds contain .6% potassium, .06% phosphorous and 2.28% nitrogen.
There was also a bit of copper and a trace of magnesium in the grounds. When applied as a soil amendment, the coffee grinds provided some nutrients right away and released some gradually.
This makes them a good choice to give your plants an immediate boost along with ongoing nutrition.
How To Use Coffee Grounds In The Garden
If you have acid-loving plants, you can feel free to simply work the coffee grounds directly into the garden soil surrounding the plants.
For plants that are not acid-lovers, use your own homemade compost that includes coffee grounds.
Be sure that the grounds have had plenty of time to break down and become less acidic before applying them.
Feed Your Lawn With Coffee Grounds
Are coffee grounds good for grass?
As a simple soil amendment of coffee grounds on lawn by just sprinkling coffee grounds evenly over your lawn.
Rake the coffee grounds on grass in for good coverage and contact with the soil.
More on Coffee:
- Growing and Indoor Coffee Tree
- Adding Coffee Grinds To The Compost Bin
Keep Pests Out Of Your Garden & Attract Beneficial Creatures
Slugs and snails hate coffee grounds, and earthworms adore them! This makes coffee grounds an absolute must-have for any garden.
Earthworms eat coffee grounds and then distribute them throughout the soil of your yard and garden in the form of highly nourishing casting of worms. This is one of the best soil amendments ever.
Your Yard & Garden Will Be A Delight For The Senses
When you use coffee grounds as fertilizer on your yard, you will never have to deal with a manure from organic matter or chemical smell from chemical fertilizers. Additionally, coffee grounds act as a natural cat repellent.
If you have had problems with neighbors’ cats (or your own) scratching in your yard, your problem is solved.
When you use coffee grounds to feed your yard, you’ll have beautiful, healthy, lush green plants in a pleasant, inviting setting.
You are sure to be proud of your beautiful garden, not to mention being proud of yourself for doing your part to reduce, reuse and recycle.
Composting coffee grounds helps prevent landfill overflow and supports you in creating some healthy, green space to benefit yourself, your family members and friends and local beneficial wildlife.
What If You Don’t Have Enough Coffee Grounds Garden Tip?
If you have a coffee maker at work, set up a separate bin for the grounds and just bring them home at the end of each day.
You can also pick up big bags of free coffee grounds for grass and garden plants from Starbucks. In fact, at most coffee shops you can get all the grounds you want, free for the asking.
Some places do not provide bags, though. Be sure to bring along your own bags or a bin just in case.
How Do You Begin?
Reading this article represents an important first step. Follow through by studying the process of composting if you need to.
Set up containers to collect your coffee grounds, and locate local sources of coffee grounds if you want to go into composting on a grander scale.
The more coffee grounds you compost, the more you are helping the planet, your plants and yourself.
I have always wondered about those free coffee grounds for your garden offered at most Starbucks. I never took them up on the offer, and pretty much decided that it was a good way for them to get rid of untold pounds of grounds and not feel guilty about caffeinating the landfills. Anyway, I have my own grounds to contend with, and that’s what got me wondering again. So off I went to internet land and lo and behold, a plethora of posts and articles singing the praises of coffee grounds in the garden, as well as a few warnings and reality checks.
Kit Smith, an El Dorado County Master Gardener, warns that adding unlimited coffee grounds to the compost pile is not a good practice. She explains that coffee grounds include the pulp, hulls and effluent of the coffee bean. Additionally, coffee grounds, though a good source of nitrogen, are acidic, and excess acid prevents the compost heap from heating up enough to decompose. She recommends that grounds make up no more than 15 to 20% of the total compost volume.
Because they are acidic, coffee grounds make good acid mulch. Of course, too much of anything is just too much, so apply coffee grounds in limited amounts. Kit recommends a layer no thicker than half an inch. Working coffee grounds into the soil will improve its tilth, but do this sparingly unless you have acid-loving plants, like camellias and azaleas.
Sharon Lovejoy, the author of Trowel & Error, extols “Our ancestors had it right. Waste not, want not—And that includes coffee grounds.” She recommends them as pure gold for your garden, compost pile, and best of all, your worm bin. She goes on to say that, “From my point of view, the invention of the garbage disposal was one of the worst moments in household and garden history. For every pound of “garbage” washed down the drain, we waste at least 8 gallons of precious water and compostable vegetable matter that could be put to good use in our gardens.
The best article I came across was from Sunset Magazine – they actually sent a batch of Starbucks grounds to a soil lab – Soil and Plant Laboratory Inc., in Bellevue, WA. The findings were encouraging – amending soil with up to 35% grounds will improve soil structure over the short and long term. They should be tilled into the soil to a depth of 6 to 8 inches and will improve the availability of phosphorus, potassium, magnesium and copper – negating the need for additional sources of these nutrients. In addition, each cubic yard of coffee grounds provides 10 pounds of nitrogen (0.09% available). The grounds will provide nitrogen in a slow release fashion for use by plants over the long term. It is an excellent soil amendment and is recommended to be used at a rate of 25 to 35% by volume to improve soil structure. The slightly acid properties of the grounds are also a welcome addition, especially here in the west where soil tends more towards the alkaline.
Don’t let the opportunity for freebie coffee grounds pass you by. Get courageous and ask your local coffee shop or restaurant to save some of their leftovers for you. Or, after you finish brewing your morning pot of coffee, take that treasure trove of nutrients and compounds out to the compost bin where they can release these compounds as they decompose and make a healthy amendment for the soil in your vegetable garden.
Put one-third coffee grounds, one-third grass clippings and one-third dried leaves into a compost bin. Mix the coffee grounds and carbon-rich matter together thoroughly with a pitchfork.
Allow the compost to develop a soil-like appearance and an earthy aroma before using it. It may take three months or longer for compost to fully break down, depending on the materials used.
Spread a 1-inch layer of moist coffee grounds on the soil in your vegetable garden. Add a nitrogen fertilizer to the soil according to the package directions. The nitrogen fertilizer speeds the decomposition of the coffee grounds and gives your vegetable plants more nutrients Mix the coffee grounds and the fertilizer into the soil with a pitchfork or shovel. Don’t leave the coffee grounds on the surface of the soil, exposed to the air and causing them to dry out; dried-out coffee grounds repel water.
Though there was not much hard research on this, many gardeners enthusiastically insist that coffee grounds repel unwanted pests, such as snails and slugs, in your vegetable garden. Personally, I would take a wait-and-see approach to this.
Finally, if you run out of room for coffee grounds in your compost bin, store the remainder in a plastic trash bin until you can use them. The coffee grounds never expire or go bad. Better yet, give them away to gardeners in need. Tea drinking gardeners can compost their bags and leaves, but they cannot be used directly in the soil, so a gift of grounds would certainly be a welcome one.
Oregon State University: Coffee Grounds and Composting
University of Arizona Cooperative Extension: Using Coffee Grounds in the GardenCity of Davis: Backyard Composting Guide
Environmental Protection Agency: Composting
How to Compost Coffee Grounds