I will let you in on a little secret that I have been harbouring for the last week or so. I am addicted and obsessed with coffee grounds, or at least my worm farm and garden are!
I discovered this wonderful organic matter about 12 months ago when a friend of mine gave me two large garbage bags of coffee grounds that he picked up from a local cafe. Without thinking too much about it, I added a bag each to two of my three compost bins. About a week later I checked back and to my amazement there were worms in abundance literally swimming though the grounds. They loved the stuff and multiplied quickly, which made me happy.
Anyway, after a while I promptly forgot this valuable lesson until about three weeks ago when I read an article about the benefits of coffee grounds when used in your garden, compost or worm farm and how it has a high carbon to nitrogen ratio (about 20:1) which is comparable to grass clippings. Coffee grounds also help the soil to retain moisture if added directly. For those who compost, it is used as a ‘green’ and not a ‘brown’ even though that is its colour. For those who thought it would be high in acid (just like a cup of coffee), think again, because it has relatively balanced pH of between 6.2 to 6.9 (with 7 being neutral). Most of the acid is flushed away during the coffee making process. If you have acid loving plants such as blueberries, you can add it directly around the base and they thrive.
Now I am a one cup a day man, which produces 20 grams (3/4 oz) of grounds. This doesn’t sound like much but over the course of a year that amounts to 7.3 kg (16 lbs) of waste. It only takes 50,000 cups of java to make one metric tonne of the stuff, which you can easily imagine many, many times over in a large city of 4 million like Melbourne or Sydney. 1 tonne of coffee waste emits 1.6 tonnes of Greenhouse gasses, primarily being methane (CH4), so that is one hell of a lot of GHG emissions just from coffee waste. Taking it out of the waste stream is doing the climate a favour!
Where do you get a steady supply of this ‘brown gold’? Well if you happen to live in Melbourne, which is home of Australia’s coffee culture, you certainly do not have to look very far. There are cafes and coffee shops everywhere, just throwing away mountains of coffee grounds every single day. All you have to do is have the courage to ask for them.
So I did ask. I currently have an arrangement with my favourite coffee lady Kate, whereby I take in a little bucket with a lid, and she diverts the coffee grounds from landfill and into my bucket. It fills in a couple of days and I collect it in the mornings and pop it into the boot of my car before I catch the train. A nice arrangement and Kate was more than happy to accommodate me, probably because I started the keep cup craze here at the train station. Anyone who is anyone now has a keep cup (well at least 15 people that catch my train now!). There are many other cafes in town, so it would be easy enough to approach them as well, but we will see how much I get from Kate each week first before I get too greedy. The worms and compost bins can only take so much.
 |
| The coffee bucket for the railway station cafe. |
Where else can you get some without doing the hard yards? Well I did some research and there is a web site that can help you. groundtoground.org has a great map with details of where you can pick up some coffee grounds from willing cafe proprietors. Have a look as it has some great tips on how to use the coffee grounds and other good ideas.
Additionally, lets not forget our work places. Many now have automatic coffee machines that grind roasted beans and serve up a half decent cup of coffee. I know that at my work, just about every floor in our high-rise has one of these machines that needs to be cleaned out daily. The grounds are usually tipped into the landfill bin by some unconcerning soul. However, the machine on my floor gets cleared by yours truly, whereby I cart the grounds home in my lunch box. The only limitation I have to taking home more is the room and weight of my backpack. I could probably carry about 3kg comfortably and there is certainly much more than that going into the bin each day.
 |
| My lunch box (after lunch of course) |
So in summary, don’t be scared to ask your local cafe for their coffee waste. It may not have any value to them, but it is worth it’s weight in gold if you ask me. It is fantastic for your worm farm, compost bin, and veggie patch, not to mention a big reduction in greenhouse gas emissions. Lock all that carbon away in the soil is such a simple action that you can take.
Best of all, coffee grounds are free!
must remember to ask around 🙂
Thanks Gavin for the reminder.
No problems Kristy!
I started doing this with one of the cafes in Glasgow city centre, then I lost my allotment plot. Am moving to Wales with a reasonable sized garden and the lanlord has permitted to grow veg – yipee – so I will soon be making arrangements as such with a local cafe. Happy Growing.
Nice one Shaheen. You should be able to grow monster sized leeks in Wales 😉
You can also grow oyster mushrooms on your used coffeegrounds! You should try it once.
Hi Anon, do you have any references/links that would help out? Sounds interesting.
There are lots of links to be found, just google on oyster mushroom growing on coffee grounds, or search youtube. Plenty of people have done it before 😉 A good book reference would be Paul Stamets ‘Growing Gourmet and medicinal Mushrooms’ (visit his website too : funghi perfecti. It is very interesting! Here is a starter for you : http://www.treehugger.com/corporate-responsibility/growing-oyster-mushrooms-in-coffee-grounds.html
Best of luck Gavin, love your posts !
Greetz from Belgium
Thanks, I will follow those up. Loved Paul Stamets TED talk as well.
You’re welcome! Let us know how this works out for you. How mushrooms can save the planet 😉
Good for you! When we had wormies we kept them in big bins under rabbit hutches with all the spent coffee grounds they could wallow in. They love it! I haven’t found a good place around here to let me have their grounds … yet. 😉 Ours go out to the compost pile with the unbleached paper filters or just by themselves. Good on ya!
Cheers Mary, get stuck into the local coffee shops. One of them should oblige.
I have a two-bucket system going at my work. I bought two 5-litre food-grade buckets with lids from Bunnings. The cleaner empties the machine into one of the buckets. When it’s full, I take it home and leave the other bucket behind. I just keep swapping full for empty, and building up my compost pile!
Strawberry plants seem to love the coffee grounds, too.
That is a great method Darren. I think I will try that out. I collected a small bucket full today from just 4 machines at work. You should have seen the weird looks as I cleaned the machines out, floor after floor!
I’ve also saved coffee grounds from work for my compost.
I haven’t tried this myself, but just read that sprinkling used coffee grounds on soil repels cats, fleas, and ants.
brenda from ar
Nice one Brenda. I have seen it repel snails and slugs as well.
I’ve been getting the coffee grounds from work for around a year now. I hate it when it’s school holidays and my worms/garden don’t get their ‘fix’.
(It’s the ONLY thing I hate about the holidays, though!)
Dear Gavin,
I have obtained a bucket of coffee grounds from my friendly coffee shop people and put them in the compost. Many thanks for your blog! However, I would like to say your N:C (22:1) ratio for coffee grounds is wrong I think. As a former scientist I like to get these sort of things right 🙂
Steve Solomon is a local gardening authority and his information is that the N:C ratio of grounds is (1:12) http://www.soilandhealth.org/05steve%27sfolder/05aboutmeindex.html(Taken from an in print book he authored and has placed on his website as an eBook: Organic gardener’s composting Van Patten Publishing Portland 1993. The book is copyrighted and must not be posted or distributed outside his site).
Steve’s book, Growing Vegetables South of Australia is a locally renowned and authoritative source of info and is in print and can be purchased from Steve.
His website has a library of eBooks of interest to sustainable lifestylers which you and your readers can look at http://www.soilandhealth.org/index.html. Some of the ebooks are protected by Copyright and should be treated accordingly. Even those out of Copyright need to be treated with respect by your readers. Always acknowledge your sources and don’t distribute them if it is not permitted!
Cheers Jane
Library & Information Professional:)
Launceston
Another great use for coffee grounds too is to wash some of them down the drain. May sound like a waste but keeps it from getting smelly. You wouldn’t need to use much or often and you could probably add it just before you plan to tip some liquid down the drain so as not to waste any water. :o)