Smoking marijuana legally in a coffee shop in Amsterdam is a breeze. Producing and acquiring weed legally in the city is another story.

For decades, coffee shops around the Netherlands have permitted customers to buy and consume marijuana legally thanks to a Dutch toleration policy. But it's illegal for coffee shops to purchase their supply of weed. Cannabis production is also forbidden.

"The most difficult thing about having a coffee shop in the Netherlands is that it's allowed to sell it, but it's not allowed to buy it," said Joachim Helms, co-owner of Green House Coffeeshops in Amsterdam and chairman of the Dutch Cannabis Retailers Association.

Now, as countries like Canada and states in the U.S. are embracing marijuana legalization, the Dutch weed market may be falling behind.

"The coffeeshop, that whole thing, is organized really well and it really has a lot of benefits, but the back door, that's where the weed is coming in, that's not organized," Helms said.