WINDHAM — Drug agents who raided a home here found more than the marijuana plants they were looking for. They discovered a high-tech marijuana factory, the most elaborate ever uncovered in Maine, officials said.

Larry McMahon, 43, was convicted last week of possession of marijuana with intent to distribute more than 100 plants. He faces a minimum sentence of five years in prison and is scheduled for sentencing this fall.

“That was the most sophisticated growing operation that any agent involved in this case has ever seen or is aware of in the state of Maine,” said Wayne Syphers, a supervisor with the Bureau of Intergovernmental Drug Enforcement, the lead drug agency in the state.

Besides 534 pot plants of varying sizes, agents last fall found high-intensity lamps connected to timers and motorized ceiling tracks so the lights could move back and forth above the plants at specified times during the day. Shiny, tin material hung on the walls to reflect the light.

The plants were grown in spongelike squares called “rock wool,” a cultivation technique known as hydroponics. An elaborate irrigation system fed the plants at regular intervals.

Carbon dioxide tanks, also hooked up to timers, helped create the ideal atmosphere to grow marijuana. Hypodermic needles were used to inject the plant stalks with nutrients.

McMahon, an electrician by trade, told Federal District Judge Hector Laffitte that he was lured into the pot business because he thought he could make big profits from it. He told the judge he had turned to a sophisticated growing system to improve his chances at making a lot of money.

Dried and processed marijuana now sells for $2,000 or more per pound, which authorities say is the typical yield of a fully mature plant. The price is high in part because the home-grown pot is more potent than ever before.

“It’s more involved than merely tossing seeds in the ground and coming back to see how they did,” said Noel C. March, supervisor of BIDE’s administrative unit. “Gone are the days of a nickel bag when $5 would buy you half a sandwich bag of marijuana.”

The National Organization for the Reform of Marijuana Laws estimates that the cash value of Maine’s pot crop is nearly a quarter of a billion dollars — making it the state’s top money-producing crop.

By comparison, Maine’s potato crop last year was valued at an estimated $160 million, the blueberry crop at $13 million and the lobster catch at about $50 million.

NORML’s estimates for marijuana cultivation are based on a combination of statistics of the Drug Enforcement Administration, of legal sources and of the state chapters of NORML, said John Dunlap, public affairs director for the organization.

The last unofficial tally for domestic pot growing was in 1987, when NORML estimated that Maine had about 94,000 plants. Officials say that estimate has grown to at least 100,000, although Maine is still one of the bottom 10 pot-growing states.