Fertilizer residue damaging?


#1

A question from a fellow grower:

I keep seeing people smoking marijuana and the ash is is dark or black. This means there is fertilizer residue left in the plant at harvest. The marijuana I smoke has a very light grey ash and smoke is smooth with none of the usual problems like coughing, phlegm, red eyes, sore/burning throat and lungs. Everyone with black ash joints seems to cough and produce a lot of phlegm and voice the above complaints. What is in fertilizer residue that causes these problems? How unhealthy are these residues since they are inhaled? I think marijuana smokers should know they are smoking crap (fertilizer) with their marijuana and that it will injure their health. I have smoked marijuana for around 50 years but the marijuana is always clean. What will 50 years of smoking the crap I see other people smoking do to them?