Known as the “Ganja Guru,” Ed Rosenthal is an international authority on cannabis horticulture, a longtime educator, activist and legalization pioneer. He was an early contributor to High Times magazine and is a professor at Oaksterdam University in Oakland, California.
Rosenthal is the author of several foundational cannabis books, including the influential Marijuana Grower’s Handbook, which since 1978 has taught millions how to grow better weed. In 2002, Rosenthal was prosecuted for growing marijuana, a case that helped sway public opinion in favor of state-level medical cannabis laws. He continues to advocate for cannabis reform worldwide.
‘Everyone Should Have the Right to Grow Their Own Marijuana’
Rosenthal has spent more than 50 years fighting for home cultivation. While some U.S. states have legalized purchase and use, he notes, growing cannabis remains prohibited in many places—like Washington state, where consumers can buy but not cultivate at home. “It’s an incomplete revolution,” he says. “We still have a lot of rights to win.”
For Rosenthal, home grow is about more than access—it’s about pleasure, health and justice. “Growing a plant is a pleasure,” he says. “When we grow, we know what we’re consuming, and we can avoid pesticides and other contaminants.”
Photo by Christian Peacock
He adds that home growing is more affordable and empowering than purchasing from licensed retailers. “It’s much cheaper—and more accessible—to grow cannabis naturally than to go out and buy it.”
“Marijuana use may not be addictive,” he jokes, “but growing it is.” For Rosenthal, the appeal is partly emotional. “Cannabis has stages of growth like a human being. There’s something deeply satisfying in nurturing a living plant.”
From Counterculture to Commodity
Rosenthal has watched cannabis shift from a revolutionary symbol to a commercial good. “The meaning of marijuana has changed,” he says. “It was once a countercultural flag. Now it’s a lifestyle, a medicine, a wellness tool for productive, rule-abiding people.”
He finds it telling that cannabis was designated “essential” during the pandemic. “The government realized: if people are stuck at home, better to have them smoking weed than drinking heavily.”
And the global reach of cannabis culture? It reminds him of music. “It travels. Just like Seth Rogen smoking a joint on TV—how far does that message go? Everywhere.”
Legalization in Perspective
Rosenthal believes California’s path to legalization was driven by both racial justice and cultural change. “Once marijuana became a medical issue, more people used it. Familiarity grew. By the late 1990s, a majority supported it.”
But not everyone supported legalization. In Northern California, many growers opposed it. “They wanted it to stay illegal because prohibition kept prices high.”
Ed Rosenthal with Snoop Dogg
Still, public opinion flipped over decades. “It took 50 years,” he says. “But we went from two-thirds against it to two-thirds in favor. Even Oklahoma—70% voted for medical marijuana. That’s a conservative state. It proves that change is possible anywhere.”
“There’s no reason cannabis has to be anything but regional,” he adds. “I don’t mind big companies—as long as people can still grow their own.”
Why California Isn’t a Cannabis Model
While often seen as a cannabis leader, Rosenthal rejects the idea of California as a model. “California is not a recipe or a silver bullet,” he says.
He criticizes the state’s restrictive plant limits, local bans, licensing bottlenecks and “unscientific” metrics. “Counting the number of plants is absurd,” he argues. “We should be measuring the canopy, not the stems.”
“People are forced to grow big, inefficient plants when they’d rather grow smaller ones with faster turnover and more variety.”
He also blasts the limited license model. “Why should someone need millions of dollars just to open a cannabis store? If they meet hygienic and safety standards, they should be able to open, period.”
Licensing, Social Equity and Class Barriers
Rosenthal believes that real equity comes from lowering barriers to entry, not just handing out limited licenses.
“If licenses were affordable, we wouldn’t even need equity programs,” he says. “But regulators restrict supply and call it equity.”
He warns that some equity programs become loopholes for exploitation. “People with money partner with impacted individuals, then buy them out as soon as the law allows.”
Instead, he calls for training and internships. “The industry should serve as a vehicle for social mobility. Give people skills. Let them move between social classes.”
Photo by Dabsel Adams
Appellations and Environmental Hypocrisy
Rosenthal is skeptical of California’s push for cannabis appellations of origin. “Most of the time, growers aren’t even using native soil. And these aren’t true landraces—they’re hybrids.”
He argues the Emerald Triangle wasn’t chosen for terroir—it was chosen for hiding. “Nobody goes up to the hills to grow corn. They went there because of the helicopters.”
And some practices, he says, have harmed the environment. “Fuel spills. Nutrient runoff. Destruction of native plants.”
Ed Rosenthal with Tommy Chong // Photo by Kerry Raynolds
The ‘Tomato Model’ for Cannabis
Rosenthal’s vision? A decentralized, open system—just like tomatoes.
“You have multinational tomato growers, sure. But you also have backyard farmers, cooperatives, roadside sellers and boutique heirloom varieties. More people grow tomatoes at home than all the industrial producers combined.”
Photo by Dabsel Adams
“That’s what smart regulation would look like for cannabis.”
He doesn’t oppose large corporations, as long as they don’t block home growers. “Progress should not come at the expense of individual rights.”
This article was originally published in Spanish on ElPlanteo.com in 2021 and appears here in English with permission, lightly adapted for High Times.
Photos courtesy of Ed Rosenthal
