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Couch grass

Me again my my newly acquired allotment is packed solid with couch grass.  I have removed two large green garden bags full from the surface. That was just from the length edge of one side of the allotment.  I have put down membrane and hope to remove whatever I can once it dies out a bit!

I know that it gives off bad toxins to other plants.  So my question is if I later on do ‘no dig’ on top of what remains after being covered will it be ok to plant things?  And what can I add to the soil to help it recover after the evil couch grass.  I will use cardboard and compost for the  planting.   Please help! 🤗


  • Unfortunately, in my experience any couch grass roots left under your cardboard and compost will quite quickly grow through both.  The shoots on couch grass roots are sharp enough to pierce plastic, let alone cardboard, as they grow.  I think I'd concentrate on one area at a time, and clear the bit you want to use as your first no-dig bed really thoroughly, then use your cardboard and compost for just that bit.  You'll still get the odd bit of couch grass growing through, but you shouldn't be overwhelmed.  Trying to clear the lot at one go, is just soul-destroying.  If you have, or can acquire, some old carpet, that is pretty good at excluding light; covering the parts of your allotment which you're not yet in a position to weed is really helpful.  Even couch grass will give up if you exclude light from it, for long enough.  Good luck!
    Since 2019 I've lived in east Clare, in the west of Ireland.
  • You probably already know that couch grass spreads by underground runners so even if you completely eradicate all of the couch grass from your plot it will return underground from neighbouring plots/paths/common ground, don't be disheartened this is the way of community gardening on allotments not everyone sings from the same hymn sheet and some plots are better kept than others, you will have to remove as much couch grass as you can on your plot and be prepared to keep pulling any out that returns.
  • FireFire Posts: 18,976
    edited 10 February
    Unfortunately, in my experience any couch grass roots left under your cardboard and compost will quite quickly grow through both.

    Yes, even cardboard and two layers of thick weed membrane doesn't seem to put it off over a year or two. It has deep roots and sharp shoots and can puncture pretty much anything.

    How do most people handle it?  It has started coming in from next door's lawn for the first time, in among rose shrubs, right against the fence - hard to get.  Next door doesn't garden and I guess it's running riot there - like the bindweed.

    Thoughts welcome.
  • DovefromaboveDovefromabove Posts: 87,903
    Continuous awareness, assiduous weeding, root barriers at boundaries and targeted application of weedkiller if you use it.  It’s a PITA. 

    Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.

  • PalustrisPalustris Posts: 4,298
    You could always eat the roots. They are reputed to be edible.
  • It is mixed in with the lawn grass in places here so it's not practical to eradicate it completely. Just monitoring the places where it is trying to spread and digging out the sideways underground growing white stems when it is going places it is not wanted seems to keep it some way contained.
    Happy gardening!
  • FireFire Posts: 18,976
    edited 11 February
     assiduous weeding

    For sure but in my plot it's coming in under a rose hedge and nigh on impossible to get to. I've not had it before and I now realise how lucky I was to have previous neighbours who looked after their garden. 

    I also understand the potential benefit of having a thick ivy hedge between terraced gardens as it stopped anything coming under - like having a metre barrier between us; now sadly gone.

    Thanks for everyone's thoughts above.
  • bcpathomebcpathome Posts: 1,302
    You will never get rid of it until you sift out ever last little bit . At a Q&A with Alan Titchmarsh I asked your question, how do I get rid of couch grass? His answer was 
    lay  6 ft of concrete over it ! .
  • bédébédé Posts: 3,073
    The traditional way with new allotments is to grow potatoes.  Remove the couch with the earthing-up and harvesting.

    I did this and found some couch roots going straight through several spuds, but the yield was unaffected.
     location: Surrey Hills, England, ex-woodland acidic sand.
    "Have nothing in your garden that you don't know to be useful, or believe to be beautiful."
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