You probably won't be able to turn up at your local dispensary after work on day one of legalization and buy a few grams, according to an inside source who says shelves may be bare on October 17.

The Ontario-based cannabis producer Aphria Inc. is warning consumers that you might have a tough time buying cannabis immediately after it becomes legal in Canada. Aphria's CEO Vic Neufeld is saying people should expect to see at least a few "sold out signs" in the first couple of weeks.

"There will not be any complete satisfaction by any of the provincial regulators out of the box," Neufeld told the Financial Post. "The pipeline fill is not going to be there. But that’s just the short term."

While Neufeld was quick to stress that this will be a short-term problem, many consumers are going to be disappointed. Current estimates suggest that the Canadian marijuana industry will only be able to fill between 30 and 60 percent of total demand on day one. And those supply shortages could take up to three months to fix.

However, even when the licensed producers start to catch up to demand, consumers will face other problems. In province like Ontario there won't actually be any brick-and-mortar shops for sometime. While online sales will be available this means individuals who can't or don't want top shop online may be out of luck.

Of course this is probably great news for the black market for cannabis, which stands to profit from this shortcoming in the supply chain.