[Lesleyk]

I'd like to know whether there is any real difference between the two, in terms of usage, or if they are truly interchangeable as some folk say.  My understanding is that vermiculite is useful if water retention is needed and perlite is good for drainage.  Any thoughts?
 

[Trillium]

There was a discussion on them here:

http://chat.allotment-garden.org/index.php?topic=99797.0

[Lesleyk]

thanks - I've had a look and it's been helpful - think I know what my plan is for this year