Anya Louise Cooper, 48, and Toby Derrick Cooper-McLeod, 21, on Monday pleaded guilty in north west Tasmania's Burnie Supreme Court to cultivating and trafficking a controlled plant.

They also pleaded guilty to dealing with the proceeds of crime, but disputed the amount suggested by the prosecution - about $30,000 in cash.

The court heard Cooper and McLeod-Cooper had been running their "large-scale" business from a home with blacked out windows for about a year between 2019 and 2020. Defence lawyer Stephen Wright said his clients' business, born from chronic pain they both suffered from, was aimed at providing alternative painkillers for humans and animals.

The operation ground to a halt when police raided their house on November 20, 2020, discovering 47 cannabis plants, cannabis seeds, growing equipment such as automatic lights and humidifiers, bongs, oil infused with cannabis, two exercise books with sale records and addresses, gummy bears and snakes infused with cannabis, bubble wrap, containers, and two wads of cash totalling about $30,000.

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Only three days before that, police had raided the Burnie Post Office and discovered eight packages stuffed with about four kilograms of cannabis gummy bears. That was followed by another raid on November 24, during which police seized nearly three kilograms of gummies.

Crown prosecutor Alicia Chisholm told the court the mother and son had been arrested and interviewed at the Burnie Police Station during the raids, where they admitted they had been growing their business for about a year.

"Ms Cooper learnt to grow from the internet and trial and error," Ms Chisholm said.

"The operation grew through word of mouth, people made contact through Facebook messenger."

Ms Chisholm said the bags of gummy bears had been sold in 150 gram bags for about $30 a bag. She explained many of the payments had been made via cardless transaction, a system in which a numerical code is issued in order to withdraw money directly from a person's bank account without a debit card.

"She told police, 'I've had feedback, it has helped people stop using their prescription drugs and harder drugs'," the prosecutor said, reporting from the interview Cooper had given police.

She added that Cooper and Cooper-McLeod had confessed to posting about 506 parcels through Australia Post, as well as occasional sales of half an ounce of cannabis for $150.

The police estimated the plants, oil and gummies seized to be worth between $115,000 and $116,000.

Ms Chisholm also alleged $30,000 found in two piles of cash were the proceeds of crime.

Mr Wright said his clients were both using cannabis medically. He begun by explaining Toby Cooper-McLeod's "very interrupted schooling" from age 10, which had been caused by a serious head injury in a car accident.

"He had been addicted to morphine," Mr Wright explained.

"Ultimately he resorted to cannabis to assist in pain management and he has now been prescribed medicinal cannabis. I ask you to take in the lack of history, he is a young man."

Similarly, Mr Wright said Anya Cooper had been using cannabis for the last 30 years to treat pain from a whiplash injury, as well as depression and anxiety.

"She started supplying for the use of people who had medical problems," he told Justice Tamara Jago.

"It is my submission you take in to account the medical history, and how they are both now able to manage their pain by lawful means."

Mr Wright went on to dispute that the $30,000 in cash police found was entirely the proceeds of crime, arguing that $18,000 of it were savings made by Cooper's other son during his butcher's apprenticeship.

Ms Chisholm argued that the record books showed the operation had easily made that amount in sales, and that both McLeod-Cooper and his mother had given conflicting statements to police about the origin of the cash.

Ms Jago adjourned the sentence and her ruling on the dispute until May 5.