Lava rock is used in KBS growing. Grow rocks do not hold the plant well enough and they tip over in the KBS style. In KBS you use one 5 gallon bucket per plant and fill it with rocks. Lava rock holds great but it is a bitch to clean. Yes the cement mixer does help a lot and a mixture of 5% bleach is easy to mix and use.

Look for a local garden landscape company you can get a whole truck load for about 50 bucks of what they call crushed lava rock.
Zandor Reviewed by Zandor on . Can you use red lava yard-rocks for grow medium ? Iā??ve heard people mention ā??lava rocksā?? as a grow medium, instead of Hydroton. Are they talking about special lava-rocks sold at a grow store, or the red lava-type rocks used for landscaping, that people use in their front yard in place of grass ? The yard kind is probably very cheap compared to Hydroton (they probably sell it by the cubic yard like soil). What I wonder is: 1) does it release minerals into the solution that would raise/lower the pH ? and 2) does the rock being red Rating: 5