Cannabis cultivation is a thriving business, whether for profit or personal use. The reasons for engaging in illegal drug growing and the effects of drug policy on it are mostly unexplored. This paper tries to shed some light on the impact of cannabis policy on this phenomenon through two models that predict first, the kilograms of marijuana herbs seized as an outcome variable and second, the number of cannabis plants eradicated. We found a significant policy effect on the number of cannabis plants eradicated while controlling for favorable outdoor (temperature) and indoor (electricity consumption) growing conditions, exports, land area, the rural population, corruption, and neighboring countries that have previously decriminalized cannabis. However, the effect on the amount of marijuana herbs seized was merely weakly significant and only in a reduced sample of developed countries.