Matthew Joseph Mayberry, 31, will be sentenced in the ACT Supreme Court on Thursday after pleading guilty to cultivating a commercial quantity of cannabis.

The charge carries a maximum penalty of 25 years and Justice John Burns told Mayberry at a Tuesday sentencing hearing that jail was inevitable.

Police caught Mayberry exiting the garage of the O'Connor house during a raid in March 2011.

A search of the property found 106 cannabis plants, worth as much as $600,000.

A court has previously heard Mayberry was wearing latex gloves when spotted.

The power supply to the house had been heavily modified.

The court heard, on Tuesday, that Mayberry's role in the enterprise amounted to that of a gardener, managing the timers that watered the illicit crop.

Defence barrister James Lawton said his client had broken the law because of his desperate need for money.

The court heard Mayberry was passionate about cars and had taken out loans to help pay for more than $50,000 worth of modifications to his 1960s Ford Capri.

Mr Lawton said a jail sentence was certain but suggested weekend detention was more appropriate.

But the prosecution said only full-time imprisonment could cover the premeditated and repeated course of offending.

The Crown said Mayberry was a small but key cog in the criminal enterprise.

The prosecutor argued most people, when faced with financial hardship, cut expenditure and sold their assets, not resort to illegal activity.

Mayberry will reappear for sentencing on Thursday.