not actually sure, since my came in a bag for me. But it should be light and really porous, and make sure its not to big to work with. Also, a lot of people recommend buying a small quantity (if buying form a pile of rock as opposed to prebagged) then letting it sit in water for a few days, then testing the pH of the water to make sure other things (like limestone dust that may have been piled near it) don't throw your system off whack.. Lava rock itself, however, is inert.
Wow, that's a nice price, Chi. I'm having a hard time imagining what the stuff is like -- can you tell me what's it made of and how big are the particles? They look quite fine. And they don't break down in water??? Have you had any problems with overcompaction?
Has anyone heard of "stone bark?"
Here's a descrip:
$115.00 / Cubic Yard.
Stone Bark?? What is this? Well, it's almost just what it says... It is a 1" rounded stone that is dark to light brown in color and VERY lightweight. Upclose, the texture of the stone looks like little "wood chips", and from a distance it looks like wood mulch instead of stone. This has been a very popular stone in the past few years due mostly to its earth-tone color and ease of installation. Approx. Weight per yard - 1,000 lbs.
Approx. Coverage per yard - 100 sq. ft. @ 3" thick.
new alternative to Hydroton: http://www.suretogrow.com/stg-storm-hail-hydroponic-supplies-from-s...
made from recyclable PET1 plastic this stuff is soft and squishy like cotton and SUPER light weight!
downside is that it is $25/cuft. it also comes in lots of different forms.