SALINAS, Calif. — This vast and fertile valley is often called the salad bowl of the nation for the countless heads of lettuce growing across its floor. Now California’s marijuana industry is laying claim to a new slogan for the valley: America’s cannabis bucket.

After years of marijuana being cultivated in small plots out of sight from the authorities, California cannabis is going industrial.

Over the past year, dilapidated greenhouses in the Salinas Valley, which were built for cut flower businesses, have been bought up by dozens of marijuana entrepreneurs, who are growing pot among the fields of spinach, strawberries and wine grapes.

“This is cannabis meets Big Ag,” said Steve DeAngelo, the executive director of one the nation’s largest marijuana dispensaries, who last year founded Harborside Farms to supply the business.

The 47-acre farm is dotted with greenhouses that emit the pungent smell of thousands of marijuana plants and warehouses where farmworkers who spent their careers tending to raspberry plants now sit in rows delicately trimming the leaves from harvested cannabis buds. When the last greenhouses are built here next year, the facility will be one of the largest legal marijuana farms in the world.