bonsaiTALK Community - View Single Post - soil question

Hey Rick -

It's debatable as to the harm of the new PT and the old PT. I wouldn't put either in my mouth. The old stuff was CCA (chromated copper arsenic) and it is both the chromate and the arsenic that leaches and is bad to you in high levels. The new stuff (which is noted on the lumber tag) is either ACQ (alkaline copper quat) or CBA (copper azole) and is less harmful or so they say. The real downside to the new PT is how you fasten it. It is corrosive (5x more) than the old PT so nails and screws need to be hot dipped or stainless. Not to worry with a grow box though. Here is a nice article on CCA and the new stuff and gardening.

The lava should be a small grade, I don't know what you get up there. I do know what size the bonsai monk stuff is. I would say 1/8" - 3/16" - 1/4" size. It would be important to me to match particle sizes with everything in the mix. In other words even particle sizes would be better than small bark, medium pumice and large lava.

4-Feb-2007	#10
Graydon bonsaiTALK Master Chief Join Date: Apr-2006 Location: Lakeland - Florida Country: United States USDA Zone: 9A AHS Heat Zone: 11 Posts: 1,004	Hey Rick - It's debatable as to the harm of the new PT and the old PT. I wouldn't put either in my mouth. The old stuff was CCA (chromated copper arsenic) and it is both the chromate and the arsenic that leaches and is bad to you in high levels. The new stuff (which is noted on the lumber tag) is either ACQ (alkaline copper quat) or CBA (copper azole) and is less harmful or so they say. The real downside to the new PT is how you fasten it. It is corrosive (5x more) than the old PT so nails and screws need to be hot dipped or stainless. Not to worry with a grow box though. Here is a nice article on CCA and the new stuff and gardening. The lava should be a small grade, I don't know what you get up there. I do know what size the bonsai monk stuff is. I would say 1/8" - 3/16" - 1/4" size. It would be important to me to match particle sizes with everything in the mix. In other words even particle sizes would be better than small bark, medium pumice and large lava. __________________ There is unrest in the Forest There is trouble with the trees For the maples want more sunlight And the oaks ignore their pleas.