Marijuana growing in Denver-based Green Dragon's 120,000 foot greenhouse.

(Grace Hood/CPR News)

How to track Colorado cannabis? It’s a growing concern. Police in states where marijuana is illegal, and even in Canada, want to know if the drug is being smuggled in from Colorado. On top of that, officials here want to be sure they're collecting proper taxes on pot. So, how to track the plants? Rick Kreminski of the Institute of Cannabis Research at Colorado State University in Pueblo tells Colorado Matters about the latest ideas for tracking cannabis, as well as the challenges. Genetic coding, isotopes and Bitcoin-like databases are part of the discussion.