As plastic bottles shuttle along humming conveyor belts in General Hydroponics' vast Sebastopol factory, a row of nozzles fills the bottles with a bright pink liquid.
The production of this proprietary mixture of phosphates, sulfates and potassium is being fueled by the popularity of growing plants indoors.
Once an industry focused on orchids, roses and tomatoes, hydroponics is now being propelled into mainstream business by marijuana.
"I used to be put off by seeing the work I did always show up in marijuana-focused stores," said General Hydroponics founder Lawrence Brooke, a scientist-turned-entrepreneur who has been developing fertilizers and water-pump systems since the 1970s.
But today, as business booms, he acknowledges the revolutionary influence of soil-free growing methods.
"People who grow medicinal cannabis know it's the most powerful tool," Brooke said. "Farmers ought to be paying attention."
He is among a cadre of business owners and gardeners who have brought Sonoma County to the forefront of a national surge in indoor farming.
More than two dozen local stores with names like Gonzo Grow in Santa Rosa, House of Hydro in Petaluma and Revolution Hydroponics in Sonoma have opened, many during the past five years.
"God knows, we've seen them pop up everywhere," said real estate agent Barry Palma, senior vice president at Cornish and Carey Commercial.
That boom is fueled by a steady hum of water pumps bringing nourishment to an unknown number of marijuana plants under an untold number of roofs.