This year the price of Dutch marijuana has increased 20 percent because the supply is being curbed by a rise in police raids on non-legal hemp plantations.
The level of THC dropped to 16 percent from 17.5 percent last year, according to a statement from the Trimbos Institute, a Dutch group that studies drug addiction and treatments.
It is the first time that the price of Dutch marijuana has risen since the institute started keeping a record of hemp prices in 1999. One gram of marijuana, grown in the Netherlands, costs about 7.30 euros ($10.30) currently.
When supply of hemp decreases and prices are on the rise there is always the risk of finding cannabis mixed with compounds such as sand and glass pearls, so says the statement. The Institute didn't find evidence that hemp sold in Dutch coffee shops has been mixed with other compounds.
Earlier this year, police in Rotterdam have shut down 600 indoor marijuana farms since 2005. There are about 6,000 active producers in the city.
Dutch officials have the task to shut down an estimated 40,000 indoor hemp plantations in total, which cause two fires a month in Rotterdam by tapping into power lines for lightning their crops. Paradoxically the crackdown is making it harder to supply marijuana shops with the Super Skunk and Purple Haze their customers crave in a country that decriminalized use of the drug in 1976.
Cannabis and the law in the Netherlands - Daily Smoker