Philadelphia police officers found a staggering stash of marijuana yesterday when they went to investigate a reported burglary in East Germantown.

Some 515 pounds of hydroponic pot, worth an estimated $2.3 million, was being grown and hidden inside a corner property on Beechwood Street near Nedro Avenue, said Narcotics Inspector Bob Snyder.

Three men, ages 44, 46 and 32, who were apparently behind the massive marijuana-growing operation were arrested and charged with a host of drug offenses. Their names were not released as of last night.

"They had a pretty elaborate operation in there, and it looks like they may have been trying to expand their operation," Snyder said.

The home had clearly been modified to support the growing operation - investigators found an irrigation system and a ventilation system to help grow the plants, as well as fake walls and a fake fireplace that could be used to hide the plants, Snyder said.

Cops initially went to the property at about 3:30 a.m. to respond to a burglary call.

When the officers arrived, they spotted the three suspects hanging around outside the home. When the men spotted the officers, they bolted back inside, Snyder said.

"Our officers chased after them, believing they were the burglars, and that's basically how they discovered the nursery, for lack of a better word," Snyder said.

It took investigators more than 10 hours to tally up all the plants and calculate their worth, he added. *