Compost Crisis?

There's been some concern in the media over the past couple of days about the risks of contracting Legionnaire's disease from growing media (aka compost) bought from garden centres. This isn't new (I saw it first reported in 2008) or proven, but it's re-emerged recently owing to a report published last week in Eurosurveillance. It summarises three cases reported in Scotland in 2008/9 where inhaling the Legionella bacterium via water droplets from wet compost is thought to have been the cause.

Three cases in a couple of years suggests the risk for any of us catching the disease from our compost is extremely low. The most common way people catch it is via the air conditioning or water system in a major building such as an office or hospital. Note it's not contagious as it's transmitted via the inhalation of contaminated water droplets. However, if anyone's still concerned, you might like to have a look here on the NHS website.

What concerns me more is the presence of glass in my compost. I bought 5 bags last year to supplement my home made stuff and two of them contained glass. The picture shows the piece I found last October whilst planting up my winter pots: the coin alongside is a 5 pence piece. The one I found earlier in the year was about 3x larger. I garden without gloves as much as possible as I hate not being able to feel the soil, so luckily I saw this piece before it found me.

I believe the move towards reducing peat in our compost is the root cause of this problem. Don't get me wrong, I'm not an advocate of peat. Despite the drawbacks of using peat-free compost I've found and commented about (as Veep) recently, I still use it wherever I can because I think it's the right thing to do. I'm sure the use of composted green waste in most peat-free or reduced peat formulas is to blame. It seems not everyone is exacting about what goes where in their waste bins and it looks like the screening process of composted green waste isn't yet able to achieve a 100% glass (or indeed plastic) free material.

What's your experience - have you found glass or other non-compostable materials in your bags? Is there anything else which worries you about going peat-free, or have you found the perfect product to tell us about?


  1. I am also concerned about the quality of multi-purpose composts. Though I haven't found glass, plenty of other bits. Last year I decided to buy seed compost to start seeds in and found it contained weed seeds - I was not happy. Also ashamed that I never got around to complaining to the company. Not sure what to use for seeds this year! Back to multi-purpose or find a different brand of seed compost. I read B&Q's is the best but that means a special journey.

    Best wishes Sylvia

  2. I had the very same problem last year when I bought a quantity of farmyard manure from a large DIY chain. The bags had a lovely picture of a cow on the front and claimed to be manure but when I opened and started using them I realised that the majority of the contents were actually shredded timber (not bark) with very very little manure. As I worked through the bags spreading them around my recently planted hedge I started to notice all sorts of contaminants, glass, plastic and most annoying to me laminate from old chipboard. It was only after it rained for the first time that I realised quite how many small chips of white laminate were now spread all around the garden. I wrote to the supplier complaining and they replied stating that as it was a localy sourced product they could not control the content. I don't agree with this as it is a mass produced product shipped to many of the stores. Sorry for hijacking, but this annoyed me at the time and you just brought it all back ;o)

  3. Difficult to imagine the legionnaire risk being very significant - you'd presumably have to be in close contact with pretty wet compost in a very warm environment before significant quantities of water vapour could get near your nose!?

    As far as contamination of compost with foreign objects is concerned, there have certainly been issues in the past - we've heard of plastic plant labels, lolly sticks, and bits of polythene being found in brand leader multipurpose composts - all originating from municipal recyclings presumably.
    Our local green waste collections are routinely spread on farmers fields rather than being routed back to consumers for this very reason I understand.

  4. Gee, I hadn't heard about the Legionnaire's/compost connection. Maybe we're simply too dry here in the SW US. Anyway, as to finding glass, etc. I don't usually buy commercial compost, so I couldn't say. I did buy a couple of bags of composted chicken manure last year to boost the veggie garden, but it came from a local source that is pretty trustworthy. And oh my, it was pretty stuff...

    I do worry about mice in my compost bin and droppings they might leave behind...

  5. Yes, we have found glass around the garden, and can guess it may have come from the bags of stuff we buy. We have been spending more to get the better quality bags lately, and that has helped. I kept wondering if someone wasn't throwing broken glass over the fence! As for the Legionnaire's, we stayed in the hotel in Philadelphia right after that was discovered in the a/c unit and the whole thing quarantined and cleaned, back in 1977. It was a very fancy old hotel, that had been hosting an American Legion convention when people began falling ill, hence the name of the disease. We stayed there for a pittance, and went to the Philadelphia Flower Show with the family. They, the family, were all allergic to the flowers and we had to leave immediately, but that is another story. I would say the glass is a greater concern. Wear gloves. :-)

  6. I use fertile fibre, which is peat-free, organic, and multi-purpose - but unfortunately also incredibly expensive. I've tried to find something cheaper in garden centres, but it's always been such awful stuff (not noticed anything like glass, just the fact that it was heavy clumpy wet stuff and most of the things I planted in it died) that I've gone back to the fertile fibre. I managed to get a reasonable peat-free veg compost for my tomatoes last year though .... but can I remember which one it was? No, I can't (doh).

    I should have thought, gardening without gloves, you'd be rather more at risk of tetanus than legionnaire's disease - and much more at risk of sticking your hand in some cat poo :/

  7. Oh golly, the worst we gotten (from the council compost) is a few bits of plastic and a whole chicken egg (with dead foetus inside, we later discovered). I haven't found anything in the bags we have bought - yet, but now I shall be eagle eyed.
    Living in Ireland we have grown up with peat just being used without thought but we do now actively buy peat-free composts etc. I think adding good old cow poo or seaweed makes up for it.

  8. Thankfully, I've never found any foreign debris in our 'city waste turned compost', it's always good crumbly stuff which I buy when what I make isn't enough. Our region has one really good company that is organic and very clean. I very much dislike peat products because they dry out too much, too quickly, so going peat free won't be too hard for me. I've been testing coir products this year which I see more and more on the market. It seems to be a viable alternative.

  9. I've heard of the Legionnaire's connection, but it seems like a bit of a panic, as it must be difficult to inhale droplets of water from potting soil. (I know some people love the smell of soil, but really.) Junk in bags of compost is a big concern. I don't buy much compost, but last year I did to build up a raised bed & found bits of plastic. Yuck.

  10. Found all sorts of bits and pieces in the compost I've bought in although no glass thankfully. Only way to do it is make your own, or if your near an agricultural college they may have some for sale that has been made by their horticultural students.

  11. Sylvia - I'm really annoyed by the amount of twigs and bits of plank of wood I have to weedle out before I can use the stuff. It's not a like for like replacement at all!

    Dave - it sounds like they were conning you. I'm sure there are standards for the bagged stuff. There certainly is for green composted waste: if it's sold for domestic use it should be 100% contaminant free.

    Nick - welcome and quite right: the risk of Legionnaire's disease from compost is tiny. You're also right re your observations on contaminants in compost. If it's not 100% contaminant free then DEFRA say it's for agricultural use only.

    Susan - I think you're OK with your mice droppings as long as you let your compost 'cook' for a while...

    Frances - you can always be relied upon to come up with a good story to add to the conversation :) As for wearing gloves, I really hate the feel of them on my hands, but I suspect I might have too if this contamination continues

    Juliet - thanks for the recommendation. I wonder if the cheaper stuff works out just as expensive when you factor in how much of the product can't be used straight away? I can feel the need for a little bit of research coming on...

    Carrie - I'd love to have access to some seaweed, but sadly we're too far away here.

    Joan - one of our local nureseries use coir but it's not so available in the shops here. I went to a talk about growing media last year - coir's very good at retaining water apparently.

    MMD - yes it's a bit of a panic and appears to be one resurfacing here from a panic a couple of years ago. It seems this debris in compost's a universal issue, not just here in the UK judging by yours and others' comments :(

    Damo - welcome! I have 10 compost bins of various sizes and still don't have enough! Besides the home made stuff is no good for seed sowing because there's the risk of damping off

  12. VP
    Well done on raising the issue about Legionnaire's Disease and compost. From what I've read, there is no direct evidence that it was the compost that was to blame. Most instances of LD come from shower heads and a/c units in offices. So did these people have a shower or go to work that day?!?
    The compost in question contained green waste and, like you, I have concerns over using green waste from the Council in my garden - one reason being the chance of finding glass and other 'nasties' in it. The other being the introduction of pernicious weeds. I know that the green waste used in bags of commercial compost doesn't come from the same sources as the stuff we can buy. Personally, I love peat composts and probably always will.

  13. I was overjoyed when our local council introduced the green bins for garden waste, and I looked forward to the day when I could buy "green manure" back from the council. However I wouldn't get any now if they paid me. One of my concerns is about pernicious weeds that may be in the compost. I have seen folk put Giant hogweed flowers/seedheads, bindweed and Japanese knotweed in their bins, even though the council has requested that these are not put in the weely bins.

    I have also found a load of dog poo in my own bin when it was parked quite near the road but still in our drive.

    And please don't get me started on what I am finding in bought in compost. Even the seed and cuttings compost seems to have large chunks of contaminates in it. How? Why?

    It makes me very sad.

    Great post VP, thank you

  14. I agree, the quality of compost has fallen dramitically. The peat free ones are full of flies and weed seeds and the reduced peat ones have god knows what in them. I too find glass and plastics. I wonder what else is in there? I think that legionaires may be the least of our problems.
    I completely agree with the move away from peat, we must preserve what is left of this specialist habitat, but when is someone going to come up a vialble alternative?

  15. I don't know where the fault lies but have on numerous occasions seen, at my local municipal "dump", non-compostable material being tipped into the "green" skip. Ok, screening should filter out most of this but some plastic, glass, builders rubble will inevitably be missed and end up in the "compost" we buy. So perhaps if we were all a little more thoughtful the problem would be lessened.

  16. Not found much rubbish in my compost so far, but have run foul of cheap peat-free composts. Now use New Horizon organic peat free grow bags - I sieve it and mix in some sand for seed sowing (actually, I didn't even do that last year and it worked fine). Also great for potting on and containers, which is just as well as I managed to create a shade garden before discovering I wanted to grow veg, so have to use pots on the patio for edibles...

  17. Thanks everyone for adding further comments.

    Geoff - I see you've added your say about peat over at yours. We'll have to agree to disagree on that one.

    Karen - you've reminded me I meant to ask whether anyone had seen a change in John Innes composts. I'm sure the bag I purchased last year was nothing like the correct formulation.

    Janet - welcome to Veg Plotting!


Your essential reads

Review: Riverford Recipe Box with guest chef Sarah Raven

How not to look after your Pilea peperomioides

Down to Earth with Monty Don

Ulting Wick: drier than Jerusalem? One of the Secret Gardens of East Anglia

Here comes the judge

#mygardenrightnow: there's still plenty going on!

Garden Bloggers' Blooms Day: Persicaria 'Fat Domino'

A clean break

#mygardenrightnow: the autumn edition

Are you looking at me?