Cotswold Stone planter - new usage

I've got a decent sized Cotswold Stone planter which I'm thinking about using as an above ground pond.  I can seal the drainage hole but wondering about how to seal the outside of the pot.
I don't want to use pond liner on the inside as it will be difficult to fit without looking crappy. I've never had this make of pot before so no idea how porous it is.  Having only recently barrowed it over the road to the garage, I do intend to barrow it back to the garden and fill with water to see what the seepage rate is.
In the meantime, I'd be grateful if anyone could suggest a sealant which I could use on the outside of the pot which would either seal it completely or at least reduce seepage to a manageable degree.
The most I'm intending to put in there is my Water Hawthorn and maybe a Cyperus ( for a while ).
Thanks in advance for any info :)


  • BobTheGardenerBobTheGardener Leicestershire, UKPosts: 8,157
    edited September 2019
    I think you need to seal it on the inside rather than the outside (or both) or it may leak or crack in the frost.  There is some stuff called "G4 Clear Pond Seal" which sounds like it would be safe for aquatic life (but best research it first.)  I think that is what I used to seal some terracotta pots to prevent them cracking when frozen (it worked, but they got broken by some clumsy gardener anyway..) ;)

    A trowel in the hand is worth a thousand lost under a bush.
  • Thanks Bob - on reflection, I think you're right about doing the inside ( at least first ! ). It's smoother on the inside too which would make it easier to apply the sealant.
    I'll definitely have a look at the G4 and give it a try.  My Water Hawthorn has spent the last 8 months in a bucket and is happily flowering so another few weeks whilst I try the sealant and check it works won't worry it ;)
    Thanks again 
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