Feb 7th, 2010
Coffee Grounds & Blueberries

I usually throw my coffee grounds in with the kitchen waste and they eventually end up in the compost bin. Yesterday, however, after I’d made my morning coffee I looked at the grounds and thought, I know, I’ll put them on my Blueberries.
Why? well mostly because they make the soil look all black and neat like new compost, but also because I understood that coffee grounds, being acidic, would make a lovely mulch for my acid-loving Blueberries. Makes sense huh?
I mentioned this on Twitter and got a reply that said when you make the coffee (ie run water through the grounds) that all of the acid is washed away. I’m not a coffee ground expert and I haven’t done said experiments myself so I turned to Google to show me the way.
It seems there is some confusion in the matter. Some sites say that grounds are virtually neutral by the time they hit the ground making them nothing better than a good mulch and worm fodder. Other sites insist that these tests were flawed and that coffee grounds are indeed acidic.
Well, I for one, am confused. Should I be wandering around the garden in my slippers at 8am on a Saturday morning with a pot of used coffee grounds in my hand or should I just chuck em in the kitchen compost as usual.
I’m thinking if they are acidic then the Blueberries are loving it. And if they’re not then the worms are loving it instead and the Blueberries are like, “it’s about time the worms got something, they have a hell of time of it.” But I can’t really say either way.
And… who knew that coffee grounds could be so useful outside the garden?






