They were called to the premises on the 11 August following a report of suspicious activity there when the drugs were found.
Growing equipment was also discovered which has now been destroyed.
Two men have been charged with the production, or being concerned in the production of a class B drug.
Pluton Kamberi, 23, of Anlaby Road in Hull and Ervis Bashllari, 31, also of Anlaby Road in Hull are due to appear before Hull Magistrates Court tomorrow.
Inspector Jon Powell said: “We are very pleased that we’ve been able to take this significant amount of cannabis off our streets, and arrest and charge two men who will appear in court on Monday.
“We’re still looking at the amount of what has been seized, but we believe it has a street value in excess of at least £1 million.
“A large amount of this drug was destined for the streets of Hull. It won’t make it there now.
“It’s not only the cannabis that we have removed but also the possibility of related crimes that go hand-in-hand with drug activity.
“We want the public to keep coming forward with any information they have if they suspect anything about drug production or dealing. We work better when we work together.
“Call us on 101 or call the independent charity Crimestoppers anonymously on 0800 555 111.”