The P.E.I. government has signed agreements with three companies to supply a total of three million grams of marijuana a year, CBC News has learned.

That's slightly less than 25 grams for each of the 121,000 Islanders over the age of 19 who will be eligible to smoke it once it's legalized on July 1.

Edwin Jewell, president of Canada's Island Garden, one of the three companies who have memorandums of agreement with the province, said he provided the province with three market reports to help them determine the right amount to buy.

He said it's a difficult call to make, but he thinks the province has it about right.

'Uncharted territory'

"It's uncharted territory," he said.

"Will Islanders use cannabis at the same rate as the rest of Canada or the same way people from Colorado would? It's really hard to say at this point."

While the territory is uncharted, there are numbers available for educated guesses.

Average consumer

Statistics Canada has been tracking cannabis use since 1961. Given that the market is mostly illegal, Statistics Canada cautions its numbers are largely provisional, but it estimates in 2017 the average Canadian cannabis user consumed about 160 grams.

Last month, a poll from Corporate Research Associates found 15 per cent of Islanders would definitely or likely purchase marijuana once it's legalized. That would put the average amount the province has secured at around 165 grams per Islander likely to consume it.

CBC News asked for an interview with the province and the P.E.I. Liquor Control Commission on the marijuana purchase agreements, but were refused.