Yeah, I'm not sure, assuming that the growing of it goes overseas, then I don't know if it'd be as glorious a bang for the buck as I initially envisioned.
However, there's always the money saved from releasing inmates held on possession and trafficking, since that costs a ton from the federal budget a year, not to mention it breeds true criminals.
We send a young boy caught with possession to jail, we turn him into a monster, since the American Jail system very seldom rehabilitates anyone. Quite frankly, I don't think any jail system can.