Introducing Coffee Compost
It’s common to hear the term ‘Coffee Compost’ used among those that collect grounds for gardening (and besides being cool to say try doing that 5 times quickly). Imagine my surprise when I was unable to find a formal definition, just general instructions on how coffee grounds can be included as an ingredient in making compost and not as the main focus of it. Just not good enough!!
This article is going to offer a definition for Coffee Compost, then quickly go through some of the steps to make it it your own backyard. And as I am fond of including photos to prove that coffee grounds are indeed excellent for all types of plants, we are going to have some of those in no particular order.
A Definition of Composts
“a mixture that consists largely of decayed organic matter and is used for fertilizing and conditioning land.”
OK so that should not be a surprise to anyone, so what would we say about a definition for Coffee Compost?
“a mixture of decayed organic matter that consists largely of used coffee grounds for fertilizing and conditioning land.”
That is probably a good place for us to start, with a shared definition.
Now putting the definition to work, the photo below is from around the root zone of an Apricot tree, with a compost made from 50% used coffee grounds, 35% pea straw, and 15% aged vermicast.
Below is a compost made from 60% coffee grounds and 40% leaves and cardboard. What appear to be very healthy compost worms have made a home in it, and it looks like a cocoon just below them, to introduce the next generation of these miraculous creatures.
I was not expecting to find 4 different worm species in a coffee compost maturing in a polystyrene container, including a large earthworm. See how rich that soil is?
How to Make Coffee Compost
Just ignore that nasty weed Eastern Black Nightshade growing at the back of the pile below. Someone more versed in gardening than I encouraged me to remove it. The next photo is a fortnight later free of evil weed plant!
Here are the main steps to make coffee compost:
- Find a spot of bare soil with some protection from the wind and rain
- Create a pile which by weight includes approximately – 40% used coffee grounds, 20% lawn clippings, and 40% dried leaves (and a few handfuls of bone meal or rock dust)
- See if you can get the pile to 1 meter high, wide, and across. This size allows the pile to generate the required temperatures for speedy decomposition
- Mix it all up really well and break-up any lumpy grass or coffee cakes (or if you have a shredder even better)
- To the top add a good shovel full of your last compost or other good quality soil (there are microbes in there that will happily spread to this batch)
- Pour in enough rain water to leave the pile damp but not dripping, and if you want to get the most of out it, add a liquid starter such as urine, fruit juice, dissolved molasses or seaweed concentrate
- Poke holes through and into the pile, enough that the contents are sitting loose. All the heat in a compost pile is due to microbes, and they need those air pockets to survive
- Now sit back and within 2 days the centre of the pile should get upwards of 60 degrees Celsius (140 F). The pile will cool down within 5 days, so keep repeating the last 2 steps until it stops heating up (this will take 3-4 weeks)
- Allow the pile to rest for at least one month, and during a wet Winter, keep covered with a hessian mat, old carpet, or a thick layer of dried leaves
- During that rest period, add as many compost worms as you can to achieve an even more potent compost
Now a week or so later, the pile has settled and cooled, enough to welcome the best of guests. I come across these big earthworms every so often, and they are a joy to hold.
Now for a sample of some fruit trees that benefit from a coffee compost, starting with a Passion Fruit on the left and a Cherry (Lapins) on the right.
Citrus trees really like a coffee compost, just as they like grounds added straight. Here we have a Lemon on the left and Tahitian Lime on the right.
And not to be outdone, on the left we have an Apple (Granny Smith), and a Plum (Satsuma).
All these fruit trees are growing well with coffee compost, particularly if it is laid 3-6 inches thick around the root zone. It prevents weeds from gaining a hold and keeps the soil moist and alive with beneficial microbial and insect life.
As a final thought, one of the best things about making your own coffee compost is how little it costs to make – even with those extra optional ingredients it will only come to a few dollars, and you know what went into it. I’ll leave you for now to enjoy the process of making your very own coffee compost – Good Luck!!
What kind of compost are you making for the garden?
- Compost – Garden, Yard and Household Waste [A Crash Course] (survivalfarm.wordpress.com)
- Leaves For Compost (groundtoground.org)
- Compost: From Yucky to Yummy (creationcarekids.wordpress.com)
Hi ! I am korean .
i intereste your blog.
Would you give to me more? about the way make compost with coffee. If you can give to me that .Kindly send to me e-male(firstname.lastname@example.org). thank you bye
Hi mate – the best recipe I have is on that post you were reading. It can be as simple as mixing coffee grounds with wood related material and add water.
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I have lately been gathering used coffee grounds from a nearby Starbucks and the workers there are more than eager to have me carry them off. Back home, I added them to my existing, but not composting, compost pile. Soon, the pile was actually steaming with composting activity and with a definite coffee aroma! I continually add more bags of spent grounds along with grass clippings and dried leaves to keep the process going. I look forward to the spring and using the compost on my vegetables, citrus, and flowering plants. Thanks for this most informative blog.
No worries Allen. Can I ask where you are from? I’m thinking somewhere in the South Hemisphere because I’m in Melbourne and Spring has just arrived.
Coffee does indeed make an excellent compost, and as long as you have some browns in there the grounds will break down into something delightful come Springtime.
Be well and hope to see you back soon!
San Antonio, Texas, USA, presently in a drought but hope for rain springs eternal! Starbucks continues to amply supply me with their used grounds. Thanks for your kind reply.
This is great information for me, and want to let you know to keep doing it. The blog is great, the articles are really excellent. Good job, cheers
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Hi! I actually work at a coffee shop in a grocery store and was wondering how you think I should go about bringing up this idea to the bosses.. Let’s just say I have picky ones. I do have an issue with how many grounds we go through in a day alone. It’s about 8.5lbs of coffee beans alone, that’s not including the espresso grounds either (nor do we make the amount of coffee each day that we are supposed to.. we quit making decaf at 11am!). We do have ONE customer who occasionally asks for whatever grounds we happen to not have thrown away. I am just not sure that we have the right population who would even do compost. I live in Scottsdale, Arizona! There are too many ritzies out here who I’m not so sure know how to get their hands dirty. Or even what dirt is, minus that it collects on their shiny cars. However we do live on the borderline of not so ritzie. It goes both ways.. our customers cannot begin to be predicted. Or the managers (teehee).
On another note, I actually came on here to ask if you think that grounds would be perfect or too strong for my orchids! I am determined to keep the suckers alive indoors in a desert. Definately will start to use what I can on our citrus trees now that I know I can! How about on palm trees, hibiscus, and gardenias? My boyfriends parents are having issues keeping them alive. They either get too much/little water or sun/heat and they need a little something extra. (The step-dad says goodday! He hails from Melbourne.) Along with complications comes his mother has a bad back and can’t do terribly much effort, step-dad doesn’t like to since we are around! (lol) We are the slaves who do most the housework.
Sorry I kind of rambled.. Thank you for your time!
I think the best way to go about this is to start taking some home for yourself. When people see you doing it they will ask, and that is the opportunity to explain how good the grounds are for the soil and plants. They might be ritzies but some of them are going to be curious?!
As for the palm trees, hibiscus, and gardenias – coffee grounds will do just fine. Try in small amounts thrown around the area until you are comfortable, and you’ll see that no harm will come to those plants.
And g’day to the ozzie – great to hear we are spread far and wide.
Thanks for writing in Shelly. Please let me know how it goes.
how does just straight coffee grounds work on banana plants?
Beth, Though it’s impossible for me to say conclusively this works wonders, I’ve put coffee grounds around my banana plants and they are super healthy with plenty of pups. Bananas are supposed to be hungry plants and I’m guessing they ate the coffee grounds with gusto.
Thanks for the reply Laura. Yes they are hungry plants and will gladly take whatever material you feed them, coffee grounds included.
So the answer there Beth is that straight coffee grounds will work very nicely.
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Can we use the plastic compost containers with a stick for stirring.
How much ‘starter” do we need?
How long does it take for each batch of compost to be created?
Hi there Deborah, great to have you here!
Ideally you need the pile 1 meter square (so high, wide, and across), to generate the temperatures required for speedy decomposition. It takes 2 months from the time you assemble all the ingredients to when it is ready to add to the garden.
If you want to do it in a compost container you really need to mix it up well, so you are getting heaps of air passing through it. The air is what feeds the bacteria, which are what generate the heat.
The compost container will generally take longer than an open pile, more like 4-6 months, but at the end of the day you end up with fantastic new soil.
As for starter, I use about 5 litres of various things every couple of weeks for a 1 meter square pile. Any of the items listed will do the job just fine.
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Have you had good luck with the proportion of ingredients you list above ?
It looks a little heavy on greens, and I think adds up to more tham 100 %.
It works beautifully Charles. I will add more dried leaves to the stack if it is looking too wet or clumpy – but like most things it is down to observation. Not sure about the amounts > 100%. I went through them again and it all looks fine??
Looks like you have answered my question – are coffee grounds good for citrus trees? Great advice will give it a go
Plenty of coffee benefits for a lemon plant Anthony. Let us know how it all goes!
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I had no idea that coffee grounds could be used these ways–absolutely amazing!
Thanks for all the great ideas!
You are most welcome Sandra, thanks for stopping by and learning more about coffee ground as compost.
I have one major problem with this – I don’t like coffee so I don’t drink it so I don’t have coffee grounds 😦 But I compost everything including a daily dose of tea leaves from my pot.
What I don’t seem able to do is to get my compost hot in mid-winter. Which only means I can “harvest” less frequently. But I use it everywhere and all my plants love it.
I like your idea of putting a tyre full of compost next to a hungry plant (your banana) so it gets a more regular feed. I may have to try that one.
No need to drink the coffee Laura! There are plenty of cafes out there that have more than enough spent grounds to give you. You won’t need to buy used coffee grounds, and that will help get the compost temperature up also.
My local Bunnings (Chatswood, in Northern Sydney) just began a trial giving away their coffee grounds for compost to anyone who wants it. I’ve grabbed a bag and will grab more in the future. I hope this trial, iniated by an employee in the restaurant, gains momentum and is taken up by Bunnings nationally.
I can feel my compost pile grinning already!
Wow Laura that just shows you what someone on the inside can achieve. I wrote to their national cafe manager earlier this year and they didn’t want anything to do with it.
This is what I wrote back in Feb:
I’m writing to let you know of a volunteer group I run that works with cafes and offices to collect and reuse their used coffee grounds for compost and fertilizer.
I am a regular visitor to Bunnings and have noticed that your cafes do not recycle the coffee grounds, and these are thrown in with the rest of the rubbish, although it could very easily be used in your nurseries or given out to customers.
There would be a good percentage of your client base that are well acquainted with the age old use of coffee grounds for gardening and I have no doubt an initiative to make use of them would be well received. There is an opportunity to make a very visible yet almost cost free statement to customers about using this fantastic natural resource.
I’ve also spoken with some of your staff running the cafes and they have been receptive of the idea, and suggested I raise it with management.
I’ll try and get in touch with that very smart person, and see if we can’t get it out to other stores.
I plan to start a vegetable garden, using the “Lasagne” method (Rodale) — Over grassy ground, spread a 2-3 inch layer of newspapers, dampen them, add mulch and topsoil; let it develop over a season, and the garden area is ready.
Using your coffee compost idea, I will vary my plan, building the coffee compost on top of the newspapers, so it will be directly applied, and ready for next summer’s garden. What do you think of this idea?
That is a fantastic idea to incorporate the coffee compost, and I’m thinking there might be more that you do with that plan…. I would suggest you get the newspaper, then coffee compost, then straw or hay, then another layer of compost, then some mulch. Give it a good soaking with seaweed extract and let it all break down for as long as you need. How does that work out?
Thanks for what you;re doing here. I have been interested in and involved with the movement (if you will 😉 toward sustainable living for maybe 25 years, and even so it’s impressive to see an entire site dedicated to dealing sustainably with coffee grounds, one of the most prevalent luxury addictions in the western world.
Cheers mate. It kind of makes sense to do something useful with all those tonnes and tonnes of used coffee grounds just going to landfill. And it so happens to be fantastic in the garden so what I would like to understand is when exactly did we start thinking of it as rubbish? How about we keep out there making a difference!!
I didn’t know anything about this! I will passing on this information to my dad as I know he will find it useful. I love the pictures, especially the worm ones!
Great to see you on the site Anne, and glad you like the pictures. If I can do anything to help let me know.
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Can you tell me about using coffee grounds on dying plants. I have some plants that were neglected and have tried all the normal things like more water or clipping or seaweed. Can coffee grounds help?
I think anything is worth a try at this stage Ray. For this can I suggest you soak the grounds in warm water for 20 minutes then apply as a liquid fertilizer. Would also be worth trying some vermicast if you have it.
You put coffee grounds in the garden all year long, and for a whole range of purposes, and hopefully this is one of them!
I save my used coffee grounds (and beg others for theirs as well) to put directly in the ground around my veggies and fruit. I have to try putting them around my potted citruses, as I like the way Shane’s citrus plants look.
I also put my cats’ fur in the ground to keep away squirrels and other rodents, as we have an urban farm. Worked a treat with a little mouse that was brazenly eating our hybrid squashes!
Wow, never thought about doing that with cat fur but it makes perfect sense. Thank you for stopping by Pat and making a contribution, and please let me know how it goes with coffee compost around those citrus trees!
I bring coffee grounds home from work and because they use plungers, I have a lot of actual coffee on the top. I’ve been pouring it either straight into the compost or giving my new citrus trees a water with the liquid. Glad to know they like coffee!
Yes citrus is very fond of coffee grounds. So much so I might go buy another lime and mandarin tree!!
I save my coffee grounds in a large plastic coffee can with a lid to keep fruit fly’s at bay. Then dump it directly in my garden using it as a mulch and till it into the soil at the end of by growing season.
Question, have you noticed or tester you coffee compost Ph? I have read that coffee ground compost is a bit on the acid side.
Thanks for writing pobept, and yes I do test pH levels often to see what impact coffee grounds are having in the soil. I actually have a post that looks at pH levels of soil from coffee grounds, and while used coffee grounds are slightly acidic, they will move to a more neutral pH over time. Most of the acid is removed by the brewing process and ends up in the cup, and nature takes care of the rest.