Marijuana is a staple product for Mexico's violent drug cartels, and traffickers are increasingly growing pot inside the U.S. to avoid getting caught smuggling at the U.S.-Mexico border, the New York Times reported Feb. 2.

There is still plenty of smuggling at the border: Mexican cartels tunnel under the border fence and even use ramps to send vehicles loaded with marijuana over the top. But cartels are increasingly setting up grow operations inside the U.S., challenging small local growers and Asian networks who previously dominated the business.

U.S. officials now estimate that Mexican cartels operate in 195 U.S. cities, up from about 50 in 2006. Cartels have become involved in indoor hydroponic grow operations inside homes and even have leased land from wine growers for illicit marijuana farms. A number of grow operations are located in state and federal parks.

Marijuana is the "king crop" for the cartels, said Rafael Reyes, head of the DEA's operations in Mexico and Central America. "It consistently sustains its marketability and profitability," he said.

Marijuana trafficking has persisted even in the face of a massive crackdown in Mexico and the U.S., which some reports claim has decreased the availability of other drugs and increased prices. Federal officials say there has been no noticeable decline in marijuana availability in the U.S., and prices have remained steady.