"The most important factor is local laws and regulations and the enforcement of those various laws. A second factor is space and climate — obviously outdoor cultivation will flourish is some places better than other. And, a final factor is sustainability of the market; indoor cultivators can produce crops on a year-round basis, providing some stability in the market over the long-term, especially in the event of crop failure or other unforeseen and unexpected disasters," Reed told us.
Yet he also said, "If cultivated correctly and with care, there should be no difference between the same strain grown in- or outdoors." And he said that from an environmental standpoint, outdoor is clearly superior: "So far as environmental factors are concerned, there is little doubt in my mind that outdoor cultivation is kinder to Mother Earth."
Wilson Linker, with Steep Hill Laboratories, Northern California's largest tester of medical marijuana, said that outdoor plants generally have more vegetative growth because of the longer light cycles, meaning that "indoor tests generally higher in cannabanoids, with THC [marijuana's main psychoactive compound] in particular."
But he and other marijuana experts also say that the quality of the buds ultimately depends on a wide variety of factors, from the strain used to the expertise of the cultivators to the time and care taken by the trimmers.
"I've seen outdoor that can compete with the best indoor strains," said David Goldman, who runs San Francisco's Americans for Safe Access (ASA) chapter, sits on the city's Medical Marijuana Task Force, and is active in rating the various dispensaries and pot strains in terms of quality, using magnifying glasses to investigate the trichomes and other characteristics. "I would match the best outdoor I know up with anybody's indoor, any day."
Even when indoor buds look better, Pearson said, that doesn't means they are better. Looks can be deceiving, he said, noting how local consumers now accept that those perfect-looking, genetically modified apples and tomatoes in the store aren't as tasty or good for you as their ugly, organic counterparts.
"It's not all about appearance," he said, noting that marijuana grown in the sunshine is more robust and complex than its indoor cousins.
"We're starting to find [outdoor] strains that were scoring just as high as indoor," says Rick Pfrommer, the purchasing manager for Oakland's Harborside Health Center.
And that's especially true when the cannabis is grown in greenhouses, where it gets natural sunlight but growing conditions can be controlled better than in the fields.
"Greenhouses can attain a level of cosmetic attractiveness that is right up there with indoor," Pfrommer said.
"There are a lot of products coming out of greenhouses that even trained eyes can't tell the difference with [compared to indoors]," Linker said. "Greenhouses are the future."
Or at least they might be the future if there is a change in the federal laws, which still view any marijuana cultivation as a crime — which is why indoor grows flourished in the first place.
Rising demand for medical marijuana has created some regulatory pushback, even in pot-friendly San Francisco, where the Department of Public Health announced earlier this year that it wanted to create a registry of growers that work with the dispensaries in order to weed out the illegal growing operations.
"In the last few years, there's been a proliferation of both illegal and legal cultivators," Dr. Rajiv Bhatia, San Francisco's environmental health director, told us earlier this summer. "We're asking for this information to try to steer them back toward legal cultivation."