I'll look into that, thanks. I have tried horticultural sharp sand in the past, which didn't work, also tried perlite last year, which did work for most of the year, but I think the little buggers found their way into the bottom of the pots. They are a reall problem for me and usually result in me having to bin all my plants instead of over wintering as they are infested by the end of summer
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I'm thinking the mesh will totally stop them getting into the bottom holes, but still let water drain out. Same with the top. Then put a layer of grit or sand on top of the mesh to hold it down.

I'm thinking the mesh will totally stop them getting into the bottom holes, but still let water drain out. Same with the top. Then put a layer of grit or sand on top of the mesh to hold it down.