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Wildlife pond without liner

Hello Gardeners,

I've only joined this website today and already have a question for those of you who have got experience with building a wildlife pond.  I garden on heavy clay and would like to build a small pond (approx. 1.5x2.5 sqm) next to a (still to be built) patio. 

As space is at a premium and because I don't really like to look of heavy boulders weighing down the pond liner around the edges, I was wondering if anybody has ever tried just compacting clay and the filling the hole with water? 

Also, I have read a bit on the internet, and apart from Butyl and PVC liners, there is something called Bentonite, which is a self-healing clay-based liner.  Has anybody here ever tried to use these?  I understand they are quite expensive.  Would they save me from having to weigh down the liner and thus lose valuable space?

Sorry, I know I'm asking a lot of questions at the same time.  Am hoping someone can help me with some of them.

Thank you



  • Wildlife ponds are easier than you think, getting a sheet pond liner is cheap and easy, then you just put gravel in the bottom, and large rocks statues etc around the edges, if you do use this method, put old blankets ad sheets and things underneath the liner so stones don't rip holes in it, if you do the pond in steps you can put aquatic plants all around it. The one I built took a weekend, it was so worth it though, afraid I can't help you on the clay base One though, sorry, hope I've been of some help.
  • DovefromaboveDovefromabove Central Norfolk UKPosts: 82,270

    You don't need heavy boulders - we've used turf to cover the edges of the pond liner and allow it to grow longer around the pond to provide the frogs etc with some cover to hide in.  This is the day the turves were laid


    And this is a couple of months later, with baskets of native plants getting established in the pond.




    “I am not lost, for I know where I am. But however, where I am may be lost.” Winnie the Pooh

  • Hostafan1Hostafan1 Posts: 33,318

    Welcome Trial and error.

    Ask as many questions as you like. Someone is bound to know whatever you want.

  • Busy-LizzieBusy-Lizzie Posts: 20,451

    A friend of mine used compacted clay, but the first time it leaked. They had professionals to do it as they used a digger and a machine to compact the clay. But sorry, I don't know the details.

    Dordogne and Norfolk
  • LynLyn DevonPosts: 21,144

    I think it would leak and you dont want that with spawn, newts tadpoles etc in there!

    I havent got boulders holding mine down, I am building a bit of a rockery at the back because the ground dropped away about 3ft due to it being built on a hill. I bought some edging to go round it, then just made a beach bit one end. I have put a few small stones in the water, the tadpoles love to get under them.

    It will look better when the plants take off this year and the edges are planted up, but definitely no need for boulders. This was only built late last summer and needs lots of finishing touches.




    Gardening on the wild, windy west side of Dartmoor. 

  • GemmaJFGemmaJF Posts: 2,286

    Yes you can use sodium bentonite to line a natural clay pond. I built one last year.



    It is a huge undertaking though requiring a massive amount of manual labour, but is doable. 

    We found plenty of advice on the internet to follow however the first attempt leaked and was a failure. 

    The second attempt used a method called the 'blanket method'  and has been successful (so far). this involves compacting a layer of the existing clay, putting in a fairly thick layer of the sodium bentonite and then applying another layer of existing clay over it to form a 'sandwich' of bentonite in the compacted clay.

    There is a thread here on the build we did:

    Do flick through it all because the first attempt failed and you'll want to see the pictures of the second go we had at it.

    It is not entirely liner free either. There is 'semi-liner' around the top edge as we found earthworms burrowed through the first attempt making it leak.

    It can be done, but a liner will be easier, quicker and cheaper, though in the long-run will need replacing in a shorter time.

    Going the natural clay route you will have to dig out far more of the clay too, as it will need to be dug out, stones removed and be prepared for returning to the pond for 'puddling' and compacting.

    I would only go the natural clay route if like me it is something you really want to try out and see what is involved, the liner method is so much easier. image

  • Thank you all for your replies and the welcome!  The photos are really helpful, too, thank you.  Your pond looks very nice, Dovefromabove, now it's getting established.  Lyn, what function has the edging you put round the sides of the pond?  Does it go directly on top of the liner?


  • PS: GemmaJF, thank you so much for sharing your experience, that settles it for me as I work on a shoestring and also don't want to dig out the clay, "sift" through it and then put it back in.  Will now definitely go for the liner option. image

  • GemmaJFGemmaJF Posts: 2,286

    Your welcome Trial-and-Error. Go for the more expensive butyl liner though, it will pay-off in the long run as the PVC ones really don't last. If you have or can get hold of some old carpets to line the pond before putting in a plastic liner, it will help too to cover any stones and stop it ripping or puncturing. image

  • wrighttwrightt Posts: 226

    Had professional to do mone and they used a very heavy compactor however there is a weeping willow near by and this soon romped through the clay to get to the water and caused it to leak so I had to call professionals back in and they had to dig a 3 foot ditch ll around it and put in some special clay granules that went like concrete as soon as they were watered. So it is possible but costly. I addition I get more wildlife in ny straight sided concrete lined pond that I do in my clay one. 

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