Quote Originally Posted by zebu111
â??How long does marijuana stay in your system?â?ť you have to realize that itâ??s very unlikely that youâ??ll be able to get a usable answer. The most common period of time is anywhere from 3-30 days, depending on your metabolism and the amount of marijuana that youâ??ve smoked. This is unfortunate, since it means that while most drug tests can only turn up evidence of other drugs if youâ??ve been taking the drug within a few days of the drug test, marijuana could still be detected in a urine test up to a month after the last time it is used.

How long does Marijuana stay in your system?
I totally agree but we were talking about hair testing and dirty hair can be removed from the head after it's had a chance to grow away from the scalp. This is where i get the 7-10 days.