Fueled by increasing demand for marijuana, illegal cultivation of the drug on public lands is causing massive environmental harm. The federal government lacks the resources to wage what would be a difficult and costly campaign to eradicate these illegal grow sites and instead focuses its limited resources on enforcing the federal marijuana ban. Marijuana decriminalization might allow legally grown marijuana to squeeze out its illegal counterpart, but the political likelihood of decriminalization is low. The key is reducing demand for the illegal drug by changing public buying preferences. However, doing this depends on an available legal alternative. This Article discusses several behavioral modification approaches as a way of changing consumer preferences and possible ways to resolve the current conflict between state marijuana legalization and its federal criminalization.