The surplus of empty houses caused by the mortgage crisis has led to an increase in the number of homes in Las Vegas that have been turned into marijuana greenhouses, the Los Angeles Times reports.

In 2010, Nevada authorities seized 153 indoor marijuana greenhouses containing more than 13,000 plants. That represents a large increase from the 18 sites and 1,000 plants seized in 2005. So far this year, authorities have discovered at least 130 indoor growth sites, more than at the same point last year. Nevada still lags far behind California, which found 791 indoor growing sites last year.

“You can’t have crime without opportunity,” William Sousa, a criminologist at the University of Nevada, Las Vegas, told the newspaper. “And all those empty homes present an opportunity for criminal activity.”

With so many homes in the state abandoned because of foreclosure, a marijuana greenhouse with dark windows and empty driveways is less likely to attract attention, the article notes. Suspicious neighbors are usually the ones to tip off authorities about suspected indoor marijuana growing sites.

Marijuana grown indoors, where temperature and light can be controlled, can be sold for more than marijuana grown outdoors—at least $3,000 a pound compared with $750, according to Drug Enforcement Administration spokesman Jeffrey Scott.