I tried this experiment last spring using old coffee grounds mixed with some silica sand. I planted a vft in the mix a put it next to several others and waited. After three months the plants in the normal mix had grown well but the one in the coffee grounds was very stunted even though it looked fairly healthy. I never had any mold or fungus develop, but the odor it developed became unpleasant so I plucked it and planted it back into regular medium. The same vft is in dormancy now and is doing very well. Granted the number of variables and the somewhat unscientific nature of the experiment, I would say it's not a good idea.
I have seen wild Sarracenia alata growing in pure sugar-white sand and S. leukophylla growing from the sides of cyprus trees at water level, but I never saw any wild plants growing in coffee grounds. [img]http://www.**********.com/iB_html312/non-cgi/emoticons/biggrin.gif[/img]