Coating with hypertufa is one solution, Guest. Hypertufa is a cement mixture with a lot of added peat. The peat allows the growth of moss on the outside of the trough givibf a natural apprearance. Make up a weak cement mixture and add a good percentage of peat. Paint the sink with a woodworking adhesive and then smear it with a quarter to half inch layer of hypertufa. Use your hands rather than a trowel to press the mixture onto the sink and mould it to a natural looking surface with your fingers. Good luck.

Do you have to continue the supertufa up and over the top and down inside the sink to below where the soil will be when it is filled Bb?

Yes Scotsgran otherwise you will have this horrible bit of white ceramic... Oh and given that we are peat free I've just smacked himself upsides the head and said tell folk to use soil improver!

lol

I also seem to remember you need to either stratify the glaze or put wire mesh on it for the hypertufa to stick to.

Sore head!!! I think that stratification or chicken mesh are alternatives to the adhesive. I should add that hypertufa troughs are not something that we often make, we tend to use polystyrene fish boxes.

Me too Bb and I don't bother with the hypertufa (I wouldn't dare admit to using peat in front of MG lol). I use a wire brush to scarify the surface of the fish box and then paint it with masonry paint. I am currently making enough to go along the top of the wall round our back garden. I will grow sedums in them to enhance our carbon footprint. I have heard of very clever and artistic persons using a hand held electric hairdryer to sculpt the surface of the polystyrene fish box before painting. NB the cement layer on your glazed sink may make it too heavy to move without doing yourself an injury.

Scotsgran once you've used the wire brush on the fish box you need to seal with a hot air gun (the sort you use to strip paint) before you paint with masonry paint otherwise the polystyrene bobbles come away. At least that is standard SRGC practice.

One big advantage of the fish boxes is that you can move them, even when planted up. Perhaps I should have cautioned that hypertufa troughs like above are best constructed where they will be displayed.

No problems with ours yet Mg.