Firefighters put the blaze out pretty quickly. It started on the second floor of a building at 19th and Shotwell streets.
Crews found the plants as soon as they got into the building. It appears this was an electrical fire caused by the lamps used in growing the plants.
Investigators think they malfunctioned and sparked the fire.
It was also a very dangerous situation for firefighters because most of the rooms were enclosed in large plastic sheets to keep the marijuana smell from escaping.
Narcotics officers tell me this would be considered a "medium sized grow."
But according to the building's owner and even Victor Martinez, the man who owns Gigler's Auto Body and Paint on the bottom floor, says the second floor was supposed to be vacant.
When asked if he was surprised that police found all the marijuana plants, Martinez said, "I'm surprised, you know. I just got the place here, I moved in two weeks ago. You know, I thought it was some sort of electrical problem in the back or so. But I never thought, you know, anything else."
The last time a tenant rented the second floor space was earlier this year. It used to be a dance studio.
Officials confirm that nobody was living there and the entire floor was used strictly to grow pot plants.
Police say they're waiting for a search warrant before they can go inside to really assess the situation and remove those pot plants.