Up to 15 firefighters from Bradford and Fairweather Green stations were on hand to battle a fierce blaze at an empty shop in Thornton Road.
The fire, at around 3.30am on 12th June, is believed to have been caused by faulty wiring after the electric meter was bypassed. The flames from the incident grew to such a severe size they were visible from outside the shop.
Two hours after they arrived, the shop was declared safe following which crew found the cellar and first floor packed with young and mature cannabis plants.
Crew manager Mick Mawson also added: “The door had been left wide open we didn't even need to break in. Whoever it was had done a runner before we got there. Someone had been living there, there was a sleeping bag.
"It was all set up with a feed and watering system as well as lights but the wiring was dodgy. The place was also full of air fresheners to try and throw people off the scene.”
A West Yorkshire Police spokesperson said: “Officers have completed their enquiries at the premise and have recovered a number of plants for further investigation.
"It is believed there were as many as 500 plants in the building, but many of these were destroyed by the fire which is believed to have broken out in the early hours of Monday.
"Our enquiries are continuing and we would ask for anyone who may have seen any recent suspicious activity around the building to contact the Bradford City Area Neighbourhood Team on 101, quoting crime reference 13170266226.
"Information can also be passed anonymously via the independent charity Crimestoppers on 0800 555111."