you want to largest or most course you can find.

Ok thanks door the help.

FYI, vermiculite will flake off quite a bit and make really fine pieces that can be a pain when they build up. Depending on what system you have, you might either want to use some fine screening to filter it so it doesn't clog the lines or mix it with a fibrous medium like coir to keep most of the flakes/dust in the root zone.

I was planning on coir, but am using Spagnum peat moss atm for no other reason than that is what I have in stock
:0)

I am actually just messing with rafts until I can assemble something worthwhile.

if you can get it use # 4 perlite and coco coir ,what has
worked best for me is 65 % perlite (4) and 35 % coco coir
i use it in hydro and containers plantings, regards.

les