RACKS of power points and a tangle of cords stretch from the floor to the ceiling.

This is the heart of a multimillion-dollar hydroponic cannabis crop in the middle of Queensland suburbia.

Police images supplied exclusively to News Ltd show the sophisticated set up of a grow house.

At the centre of the operation is the electricity supply, with a multitude of lights run from banks of power points.

Detective Inspector Michael Trezise from the state drug squad said growers bypassed electricity meters to avoid detection and cost.

``Hydroponic cannabis requires large quantities of electricity,'' Insp Trezise said.

``Some offenders have manipulated the power supply which is quite dangerous to both themselves and the community.

``They try to bypass the meters which is particularly dangerous.

``There is certainly some suggestion that someone with a electrician's background would have been required.''

In this case, about 80 cords provide the electricity for lights which can operate around the clock through automatic timers.

Entire rooms are filled with plants, but neighbours may be completely unaware of the green thumbs next door.

``They have to try to conceal the smell. They do that by utilising filters,'' Insp Trezise said.

Blacked out windows, vacant houses, people coming at odd hours, bags of fertiliser arriving and extraction fans are telltale signs of a grow house.

Since the start of last year a hydroponic team in the drug squad has located 191 separate set-ups that have varied in size and sophistication.

``Some were large and contained 100-plus plants. Some were small and contained a few plants. They were at varying stages of development,'' said Insp Trezise.

``Plants these days are genetically modified and a plant can be a fairly significant.

``You can have three plants fill an entire room. It's sort of like a bonzai situation where they are very thick, heavily budded, genetically modified to create large quantities of buds on a single plant.''

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