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Coir Compost Blocks

Hi Fellow Gardeners

I am considering buying some coir compost blocks instead of my usual gro bags (which I use as potting compost).


  •  They are lighter to store and carry around.
  • They are roughly the same price as gro bags if you buy it in bulk, and are delivered to your door (I'm not getting any younger!)
  • Organic.
  • They won't mess up the boot of the car thereby earning brownie points with patient Hubby! image


  • when I first used coir when it first came out, it was very dry and wouldn't retain moisture.
  • Can't use it for seeds.

Anything I've missed?

I have heard that coir is now much more moisture retentive (Monty likes it) - true or not?

I'd really like to hear what other gardeners think of this, I use my own compost but I simply can't produce enough to provide for my 15 baskets and numerous patio pots.




  • Nicola756Nicola756 Posts: 7

    I've been using the gardman coir blocks for the last couple of years and I like it. I don't have a car so getting compost up to the allotment on my motorbike has always been a challenge, but these compressed blocks make it easy. 

    Take your time soaking the dry block to start with - I use a big tubtrug, add water and just leave to soak for a while. After half an hour or so, hack at it with a hand fork to break the block up a bit, leave to soak some more then stir the mix to make sure all the dry bits are in contact with remaining water. It does take a little while but worth the effort.

    The resulting compost holds water really well and has the granular fertiliser already mixed in (although a regular seaweed drench goes down well) so is good enough for most planting - I've used for everything from pricking out seedlings to filling baskets and tubs. End of season, the used stuff then gets chucked onto my veg beds to help lighten my heavy clay soil image 

    Downsides - can't really use for small seeds, although I have successfully grown peas and beans. Also can be a more expensive than 'normal' bags of compost. If you're used to standard composts, it's a bit more difficult to work out when pots need watering as the surface doesn't seem to look any different when dry, just stick your finger in instead.

    hope this helps!


  • Thanks Nicola, that really helps.

    There are big blocks of coir for sale on ebay where each block makes 70 lts of compost (cost £20.99). Is it generally possible to cut bits off in order to make up a smaller amount in a trug, or is it generally too condensed to cut in your experience?

    I am really attracted by the weight of this stuff, I have a bad back and it would be so useful to be able to move compost around without straining my back.

    The ebay coir is here, just for information.

  • Tropical SamTropical Sam Posts: 1,488

    IKEA sells it cheaper than ebay. If you go abroad in the EU then look in supermarkets as it seems more freely available on the mainland.

    What would you use Coir for? I used it for tropical plants and for seedlings (as it is damp but open thus great for preventing dampening off etc)

  • Nicola756Nicola756 Posts: 7

    Lancashire Lass - that looks a decent price. I've used ksingletonsv on same site, similar prices I think.

    I've never attempted to break chunks off the blocks, think it'd be too much effort as it's so compressed and anything I don't use immediately goes into an old compost bag until needed. You can get smaller blocks (10l or so) if you only want a bit of compost which I imagine is a lot simpler.

    Checking up a bit more now, seems more people are using coir as a seed compost, mixed with perlite. Might have another go myself with some spare seeds...


  • steephillsteephill Posts: 2,813

    £21 for 3x70 ltr. of compost? Decent price? That is very expensive and very, very poor value for money.

  • You can use it for seeds, if you mix it with sand (50/50).


  • Nicola756Nicola756 Posts: 7

    Steephill- I know it sounds expensive, compared to normal compost. However I use coir for a variety of reasons.

    Its compressed size makes it convenient to transport without a car. I know that a lot of places will deliver - to my home. But I want the compost at the allotment, an unmanned site a couple of miles away and usual delivery companies won't drop off as it's not a residential or business address. My local hardware store is the only one that delivers there but they are notorious for poor quality compost. Okay, it's 3 for £10 but then add on £5 for delivery and knowing that plants wont do very well out of it anyway.... I could also borrow a friend with a car, again difficult as both of us work full time/ different days and I can't do that too often without becoming a nuisance.

    I'm trying to go peat free. Local nursery is charging £6-7 per 60l bag for the vital earth mpc. So not much difference.

    Its reliable. I'm happy to put almost anything in coir knowing that it'll grow well. Looking at the compost review threads shows a big variation in quality and each year turns into a game of finding a decent mpc.

    And there endeth my reasoningimage

    sorry for the essay!

  • SupernoodleSupernoodle Posts: 954

    Monty showed a metal tool to make seedling pots out of coir compost a few weeks ago.  Does anyone know where I can get one? Or at least what it's called so I can search for it?

  • Steephill, the price of the coir is 210lt/£21, giving 10p per litre.

    Gro bags are £3 now and contain 33lt which is 9p per litre so actually very comparable. If you know of anywhere I could get coir cheaper please let us all in on your secret supply.image

    I know you can get compost in bulk cheaper than gro bags, but I simply can't carry that amount of compost and although my Husband can and will carry it, I don't really want him to.

    The reason I need to cut into the coir if I got a big block would be because of the container size that I would have to use to make 70lts of compost - that is quite a big container! I am happy then to decant into empty compost bags. I think I will email the ebay seller about this aspect and I will get back to the forum with their reply.

    I think I would use the coir mixed with my own compost and perlite with some blood, fish and bone, so it would become a multi purpose compost.

    Nicola, I too have heard that coir can now be used for seeds and Monty obviously does this with his (I was going to say "tool", but I wont...image), his seedling pot gadget.



  • SupernoodleSupernoodle Posts: 954

    anyone know what ph it is?

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