P91 is a native strain to north county San Diego. The "P" stands for Poway, a small north county San Diego town, and the "91", meaning 1991, the first year it was introduced.
Story goes when the breeders got busted in 2003 by the DEA on "Operation Grow Up", 24 people arrested, 3,119 plants were seized from 20 sophisticated indoor grows in the Rancho Penasquitos, Del Mar, Encinitas, Carlsbad, Oceanside and Escondido areas that would have brought in about $2.3 million a year, selling about $4,000 to $5,500 a pound.
These are reports from the DEA, but these reports are hard to digest since noone would pay those numbers, even for top shelf bud. The agency said it was the most high tech grown they have seen and the highest THC content on record. Although these unfortunate breeders were not the originators by any means of P91.
It was around San Diego before the mass production these breeders produced. P91 is a clone only strain, it is a cross of Northern Lights (Thai x Afghani) cubed. Which bascially means males acquired off the original mother plant where crossbred back with the mother 3 times.
P91 has a very strong body high and almost hallucinogenic at times. It has a distinctive potent flavor, and a brain freezing citrus odor. Other native San Diego strains include Bullrider and Hogsbreath.