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Re: Blackboard chalk

> From: "Roger S. Miller" <rgrmill at rt66_com>
	(big snip)
> 3) inserting some crumbs of white blackboard
> chalk (CaCO3) into the substrate around the plant 3) adding some boron
> (from borax?).

	Backboard chalk isn't CaCO3, it's gypsum, CaSO4.2(H2O).  It will
still do as a calcium source.

Paul Sears        Ottawa, Canada