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Perennial Weeds & Composting

GlenjjonesGlenjjones Posts: 146
in Problem solving

I have this year pulled a lot of couch grass and creeping buttercup from my flower bed, and without thinking about it have placed all pulled weeds into my "Dalek" compost bin. I also have a good ratio of browns thrown in for good measure. Only yesterday it occurred to me that these are perennial weeds and so will need longer (up to 2 years+) to compost to ensure that they are dead and composted.

As I have 2 other smaller half pallet compost bins, I am now planning to use these smaller bins (with no perennial weeds) for shorter term compost making (6-12 months) and leave the "Dalek" with the perennial weeds in and light excluded for at least 2 years before using the compost.

I have 2 questions for anyone with far more experience than me in composting. Firstly, do you think my planned approach would work, and has anyone else successfully "cold" composted perennial weeds? Secondly, if I was to use some of the compost from the "Dalek" in say 12 months time but sieve out any un-composted bits or anything that looks like a weed root would that prevent or minimise my risk of having any of the perennial weeds grow from the compost?

I would be interested to here your thoughts, but I might just give it a go and update you on my experiences.

Posts

  • Blue OnionBlue Onion Posts: 2,995
    I have major issues with couch grass.. I image it and creeping buttercup would rather enjoy your cold compost.  I suggest you put the weeds in a bucket of water for a few weeks before dumping them into the compost.  Unless the buttercup has seeds.. in which case, send it off the green waste! 
    Utah, USA.
  • Hostafan1Hostafan1 Posts: 34,889
    Please don't worry about it. 
    When I empty my bins  and find something alive ( white healthy roots ) I just chuck it back in to the new bin for another go. 
    Avoid couch grass if you can , but , in my experience, buttercup rots down fine.
    Just filter it out when you're turning / emptying it out.
    Devon.
  • LynLyn Posts: 23,190
    I don’t put couch grass, buttercups or ground elder in mine. 
    Gardening on the wild, windy west side of Dartmoor. 

  • wild edgeswild edges Posts: 10,497
    I like to incinerate mine and compost the ash.
    If you can keep your head, while those around you are losing theirs, you may not have grasped the seriousness of the situation.
  • cornellycornelly Posts: 970
    Dont worry I do as Hostafan1, anything not composted gets returned for another year, I have two pallet sized compost heaps, empty one a year, two years to fully rot.
  • GlenjjonesGlenjjones Posts: 146

    Blue Onion, the compost bin completely excludes light, so the weeds will eventually die, but I know from previous experience, albeit on a much smaller scale, that it could take several years. They were all from early spring growth, so no flowers or seeds, so no worries there.

    Hostafan this was my thinking. give it 12 months and then sieve out the finer composted material returning everything else to the bin, and topping up with fresh material. the aim being to sieve out all (more likely most) of the perennial weeds that could potentially regrow. I don't know how well this would work but, I'm willing to give it a trial using this compost on only a small area of my garden first, and if successful I will continue with this approach moving forwards.

    I will update the thread as I get updates.

      



  • GlenjjonesGlenjjones Posts: 146
    Thanks Cornelly, my biggest concern was that as my heaps/bins aren't that big I wouldn't get the heat needed to kill the weeds, so I am keeping the perennial weeds in the "darlek" bin to exclude the light to weaken any potentially live weeds in the compost. I figured that this along with sieving the compost before use to put any in-composted material back in would give me a good chance to prevent the weeds re-growing. 
  • tessagardenbarmytessagardenbarmy Posts: 346
    I use my old plastic trug carriers, you know they always start to break round the handles, fill them with water and make perennial weed soup for weeks before putting them anywhere near my compost heap. I've cold heaps too and on the allotment couch, dock, thistle, dandelion, creeping buttercup and butterburr, not to mention ground elder all with very persistent root sytems unless I do this to them first.
  • Blue OnionBlue Onion Posts: 2,995
    Glenjjones said:

    Blue Onion, the compost bin completely excludes light, so the weeds will eventually die, but I know from previous experience, albeit on a much smaller scale, that it could take several years. They were all from early spring growth, so no flowers or seeds, so no worries there.

    I find couch grass, because it grows on from runners.. happily sends tendrils and roots out into the deepest dark places.. like 5ft under quality groundcloth and gravel.. surviving quite happily on the sunshine the parent plant gets.  As the others said, you'll probably be fine, especially if you do not have anything growing near to your bin.  I just run on the side of careful, as it's already enough of a battle in my garden.  I have it all throughout my grass.. which I don't mind.. but the problem is it sends on runners up into my raised beds, etc.  I would be concerned it would root in the compost bin and then send runners under the ground to outside for sun light.  

    I throw my couch grass and bindweed on a pile behind my rhubarb to open compost.  The roots and plants soon dry out, dying in a few days and then eventually composting down.  There is enough material on there that they are held well above the soil, so there is never a chance for them to regrow.  
    Utah, USA.
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