Ever since my family and I moved house about two years ago, I’ve become quite fanatical about composting. We probably would have had a compost before this, but we didn’t have an outdoor area to keep it.
I make every effort to put as much food as possible into the compost instead of throwing it out in the rubbish, and that includes coffee grounds. So in my experience, yes, coffee grounds are compostable.
You see, my mum loves gardening and so I grew up with a compost bin. Emptying the inside compost bin into the outside one was part of my regular chores, if I wanted to get my pocket money.
As a young kid, I believed that because we did it, everyone did it! Not the case at all. It seems like an incredible waste to throw out food scraps into the rubbish, to just end up in land-fill.
This led me to begin researching if there’s things that perhaps you shouldn’t be putting into the compost bin, or if there’s at least a right way and a wrong way.
Are coffee grounds bad for your compost?
According to the Gardening Australia website, it’s ok to add coffee grounds to your compost. It’s very important that the coffee grounds mix with other organic matter though, as they’re too acidic to just add straight to your garden.
This article also mentions Stuart Rodda who had great improvements to their garden after beginning to use coffee in their compost.
Stuart receives used coffee grounds from a scheme in Melbourne called Reground that collects used coffee grounds from cafes around Melbourne specifically for composting. What a brilliant idea!
Another view from curiosity.com is that adding coffee grounds to your compost is the last thing you want to do.
This article touches on various reasons why this might not be a good idea and backs it up with references to research that’s been done on coffee.
One of the main points is that there is still caffeine left in used coffee grounds, which can be bad for bacteria. Bacteria that help your compost to break down.
In my personal experience, I haven’t noticed any decrease in the breakdown of my compost or lack of insects and things in it. It’s been business as usual in my compost.
Perhaps it’s because most of my coffee drinking happens at work during the week and not at home, so I’m not adding a lot of coffee to my compost.
I use my espresso machine at home or my AeroPress with a paper filter.
Paper filters are also fine to add to the compost, however they’re considered brown, not green compost.
Are coffee grounds brown or green compost?
Coffee grounds are considered green. This is because of their carbon nitrogen ratio, which is 20 parts carbon to one part nitrogen.
It’s important to balance your compost with green (nitrogen rich) and brown (carbon rich) matter.
Read this article from The Compost Gardener for more info.
Coffee grounds and garden pests
I noticed that there’s also a lot of talk about coffee grounds being a bit of a deterrent for some insects, particularly snails and slugs.
While I would never add unused coffee grounds to my garden like some websites suggest (I couldn’t bring myself to use it for something other than drinking!), Gardening Australia again mentions adding used coffee grounds to your compost as being ok.
Not only that, but they even show you how to make an insecticide from coffee. Watch the video on the above link for full instructions.
Do you add coffee grounds to your compost?
What have been your results?
Let me know in the comments below.