A chap I do a bit of gardening for had a couple of his borders flooded
last year by a change in subterranean water flow. That has been fixed,
but the borders are still "sticky".

He wants to dig sand into the borders. Fine, but he has specified
"horticultural sand". I think it would save him money if I just used
ordinary sharp (concreting) sand from a builder's merchant. What does
the team think?

TIA

John