IT'S the criminal enterprise that has green shoots growing in almost every county.
Cannabis growhouses are sprouting up as criminals exploit the demand for high quality herbal cannabis which is pushing street prices to a record high of €25 a gram.
The growhouses can be set up quickly and easily by fitting rented property with lighting and irrigation systems to cultivate hundreds of cannabis plants at a time.
Up to recently, the lucrative racket was dominated by Asian criminals, mainly from China and Vietnam.
But local gangs are now muscling in on the trade and pushing the Asians into minority partnerships.
After start-up costs of between €5,000 and €9,000, the growers can see a profit of around €170,000 from an eight-week crop. Many are now developing a multi-crop cultivation programme. This guarantees a fresh rotating crop every four weeks, maximising the profit and helping the gangs to cope with the increasing demand.
The new drugs phenomenon led the Garda National Drugs Unit (GNDU) to establish Operation Nitrogen, which last year resulted in the seizure of more than 700 growhouses with more than a 10th of them linked into organised crime.
So far this year the unit has uncovered 350 houses and seized more than 13,500 herbal cannabis plants which have a street value of around €5.4m.
"There is no organised crime gang in the country at the moment that does not have some involvement in cannabis cultivation although some are still continuing to import from overseas," a senior garda officer said last night.
"The homegrown stuff is of very high quality but the amount being produced in the houses is not sufficient for large-scale trafficking. You could get 15 kilos per crop of 350 to 400 plants and you need several houses on the go to make it worthwhile.
"Despite the recession, the price is still shooting upwards. It was €12 a gram a year ago and has now doubled. Demand for herbal has taken over completely from cannabis resin and the quality produced from the houses can be particularly good, especially if Asians are involved."
After rows with Irish criminals over payments, many of the initial Asian growers have left the country. But, according to the gardai, some of the major gangs have signed up the Asians to work with them and guarantee a better crop.
"The Irish won't live in the house with the crop because of the sweet, pungent smell of the cannabis and use timers to regulate the watering of the plants.
"The Chinese gang bosses use Vietnamese house minders, who stay indoors throughout and even have their food brought to them. They can earn around €1,000 a week and this is huge money for them to send back to their families," one officer said.
Gardai have established that local criminals are now banding together for the cultivation business with up to eight in a gang.
They look for large rented properties in isolated rural areas, where they can convert them into growhouses without attracting attention. They prefer properties with long avenues such as the house raided by the GNDU on Tuesday in Ballyboughal, north Co Dublin.
Two rooms and a garage had been kitted out with a sophisticated irrigation system and gardai seized 350 plants in different stages of maturing. Gardai believe a north city crime gang was behind that operation.
The gardai also delivered another financial blow against a Chinese gang when they uncovered a growhouse in Portarlington, Co Laois, on Wednesday night and seized 400 plants.
Some 90pc of finds are as a result of intelligence and tip-offs from landlords who become suspicious of their tenants' activities.