"Andy Hunt" wrote:

Hello Andy

AH My dad however has advised me not to, he says that this sand
AH contains lots of chemicals which won't do plants any good,
AH because it is building sand.

This may be a local thing, but down here "building sand" is a 50/50
mixture of soft and sharp sand. It does drain, but not as well as 100%
sharp will.

AH The sand has been outside in the rain for at least 3 years -
AH does anyone know if my dad's correct about this, and if so,
AH whether the rain would have washed the sand clean by now?

Building sand can have high concentrations of salt in it - "washed
sand" is commonly available and may be implied depending on area, but
there's unlikely to be anything else - any mortar additives are put in
during mixing, or with the cement - never with the bulk like sand,
AFAIK.

And three years of rain will certainly have washed that lot out. The
only "harmful additives" you can expect are cats turds if it has been
uncovered for that length of time.

AH Even if it is full of chemicals, if I just use it for an
AH inch-thick layer of drainage material at the bottom of each
AH pot, would it be OK?

Should think so.

--
Simon Avery, Dartmoor, UK Ý http://www.digdilem.org/