usually dosent smoke his own stuff.
person2: my Dr. Greenthumb
person1: oh that dude that stands in the ally by safeway with the afro and trench coat and box of lighters?
cop1:that guy in the hoodie over there is a Dr. Greenthumb
cop2: i know but he never has any on him or at his house.
It can be found on their fourth album, imaginatively titled 'IV'.
Its subject matter relates to the above definition (i.e. Marijuana use, or a nickname of someone proficient at its cultivation).
Yeah, it's fucking cool. Pass that joint.
Me: "Roll another Blunt"
Dr Greenthumb: "Okay, but i wont use that much weed"
(A few moments and grams of weed later)
Me: "Thats a FAT Blunt, Light it up"
Dr Greenthumb: "Thats some BAAAADDDDDDD WEEEEEEEEDDD"
(Bad meaning good, of course)