Coffee grounds

Invicta2Invicta2 Posts: 663


Currently I add my coffee grounds to the compost heap. Someone has told me they make good mulch for Blueberries as they are acid. I grow my blueberries in pots with ericaceous compost, any advice on whether this is a good idea?



  • pansyfacepansyface PEAK DISTRICTPosts: 11,965

    Hello Invicta2. 

    I have never heard of it before. You could try it out on one pot and not on another and see if it makes a difference. The report back. This could be a first!image

    Apophthegm -  a big word for a small thought.
  • SupernoodleSupernoodle Posts: 948

    i looked this up some time ago and there seemed to be mixed opinions.  

    Some said shouldn't do it as needed to be composted down first as the nitrogen isn't readily absorbable and will actually rob your soil of nitrogen whilst the soil bugs do it.  Plus  coffee grounds aren't actually acid- what you drunk was.  

    But then others say they are indeed slightly acid and although the nitrogen in the grounds is not immediately available there are other trace elements - magnesium, copper etc - that are.

    So seems to be a confused area.  Like Pansy says, give it a go, and let us know! Perhaps you could do a Monty style trial - half with, half without...

  • [Deleted User][Deleted User] Posts: 0
    The user and all related content has been deleted.
  • I think I remember hearing somewhere (probably on here) that they are good for preventing slugs? not too sure why or how... (or if that is actually true...) 

  • I've heard about the use of coffee grounds to repel slugs, a friend who shuns instant uses hers for this but its like every slug repellant only partially effective!


    As for ericaceous - ness I chuck my used tea bags  where I have plants that like these conditions as tea is a camellia... Also helps hold moisture in


  • Invicta2Invicta2 Posts: 663


    thanks for the suggestions, I will restrict use to one pot and see what happens. I did try them as slug/snail repellent, they didn't work at all. Maybe I should have used one of those cheap horrible tasting brands of coffee. They do have discriminating taste, they cheerfully munch the leaves of my Timperly Early rhubarb but don't touch the Raspberry Red.

  • ninnin Posts: 186

    Hi Invicta2

    I  regularly use  bags of coffee grounds from my local coffee shop (good excuse to treat myself to a posh coffee) i use them all over the veg patch in the compost and they are great, i think they really help the plants.

    I have noticed that if you put grounds on top of a large area and let it dry it then makes a waterproofing barrier, so not good for watering. I tend to mix in with the soil.

    With regards to slugs have experimented putting a handful around the odd day time slug and no they do not like the coffee, i believe it dehydrates them slightly, to this end i put a thick ring of coffee grounds around the edge of the bed and a ring around any individual vulnerable plants.This allows water to get to the plant but makes an off putting barrier.

    I think if i ground coffee at home it would be coarser than from the coffee shop and work better against slugs like grit but that's just a guess.

    I grow mainly veg and fruit and have neutral soil and i think coffee grounds  work.

    The other bonus comes at watering time the whole garden smells of fresh brewed coffee which is great. I have manured a bed for future use with semi rotted manure and the coffee on top masks the smell nicely.

    I think what i am saying is if you use coffee grounds alongside  well rotted manure, general plant food and compost either made or brought coffee doesn't hurt. Coffee grounds are also free from the coffee shop just ask for the contents of the bin.

    One point is apparently decaf is no good for stopping slugs or for plant food no idea why, it does no damage so when its in the bag from the coffee shop i just mix it in.

    Hope this helps its just my experience based on personal experimentation in the last two years.


  • ItalophileItalophile Posts: 1,729

    Used coffee grounds have lost most of their acidity during the coffee brewing process. I put ours on the compost heap.

  • Orchid LadyOrchid Lady Posts: 5,800

    I have learnt quite a lot about acid loving plants since being on here, before I never even used to feed any plants....oops image

    I have been keeping tea bags and also any tea left over in the pot and at the end of the day mixing it all with more water in the watering  can and watering all my acid loving plants with it......blueberries, azaleas, rhododendrons, camellia etc.  My Azalea has flowered for the first time since I've had it so it must be doing some good.  Also my rhododendron has buds but they usually don't open and fall off, it actually looks like the buds are about to open.  As for my Blueberry, well bird and dog permitting it looks like a good crop this year image

    As for coffee and slugs, I mix mine with egg shell and it seems to work, well it must do as I ran out and the little blighters got my sunflowers!  All sorted and coffee and egg shell back in place now image

  • Invicta2Invicta2 Posts: 663

    Blueberries do seem to want different conditions from other acid loving plants. I garden on a heavy acid clay. Camellias, pieris, rhododendron and Azaleas all grow successfully in my garden. When I tried blueberries in the soil they were miserable and died in the winter. They have flourished in the ericaceous compost.

Sign In or Register to comment.