Gauging the greenness of CBD-laced products is trickier, since it’s difficult to ensure that the extract came from an American growth operation—as opposed to one in China—let alone a sustainable one. However, these brands tout their eco-friendly practices: Charlotte’s Web, which sells hemp-derived CBD oil, uses ladybugs as a pesticide and relies on cover crops like oats and rye to help slow land erosion. And the California-based Humboldt Apothecary, known for its THC and CBD tinctures, works with some operators who use farming methods that restrict irrigation. While states consider ways to clean up cannabis, we can all help by urging the government to study pot’s impact on the environment, and pushing to find out where that Acapulco Gold, Maui Wowie, or Panama Red really comes from and how it was grown. —R.J.Z.