The liberalization of marijuana policies is a growing global phenomena. The cultivation of cannabis can significantly impact the environment with negative collateral effects that are often unknown or overlooked. Some estimate that 60%–70% of the marijuana consumed in the United States is grown in California. Focusing on this region, we pose three main arguments. First, the environmental harm caused by marijuana cultivation merits a direct policy response. Second, current approaches to governing the environmental effects are inadequate. Last, neglecting discussion of the environmental impacts of cultivation when shaping future marijuana use and possession policies represents a missed opportunity to reduce, regulate, and mitigate environmental harm.