The medical cannabis industry is an estimated $1.3 billion-a-year cash crop in California alone these days, and an estimated 2.5 percent of Oakland properties have a chronic grow-op going. Fueling most of it is advanced hydroponics, which offers growers a semi-clandestine way to indoor garden by substituting rock wool or ceramic pellets for dirt. Add in irrigation, nutrients, timers, high-intensity discharge lighting, carbon dioxide generation, and ventilation, and it’s even more complicated than it sounds. The folks at Berkeley Indoor Garden know what they’re talking about, and they convey it with minimal ‘tude, dude. In the business since the Eighties (before it was trendy), Berkeley Indoor Garden sports a comprehensive, well-priced selection of nutrients, lights, mediums, ballasts, and much more in a large warehouse on University Avenue. The space allows for low-profile re-ups, which is always a good thing. The super-knowledgeable, courteous staff has become a rarity in the cutthroat hydro supply biz these days. That’s why aspiring Ed Rosenthals of all stripes continue to flock to this East Bay hydro shop.