Topic is in reference to the beneficial use of organic activated vegetable charcoal in gardening. We're not talking about that bag of BBQ biquettes on your deck ... Those are laden with incendiary fluid.

Some adenium growers add activated charcoal pieces (made with coconut shells, bamboo, etc.) to their substrate or dust the roots with it before repotting.

http://healingtools.tripod.com/char_gard.html