North Carolina wants to know if marijuana could one day replace tobacco as a cash crop. Louisiana is wondering how cannabis holds up in high humidity. And Washington state has questions about water supplies for weed.

Colorado agriculture officials this week briefed officials from about a dozen states – some that have legalized cannabis, others that joked their states will legalize marijuana “when hell freezes over” – to go over the basics of marijuana farming and swap stories about regulating a crop that the federal government still considers illegal.

The Colorado Department of Agriculture is also working on the world’s first government-produced manual on how to grow marijuana. There’s no shortage of how-to books catering to growers both in and out of the black market, but Colorado’s forthcoming guidebook aims to apply established agronomy practices to the production of marijuana.

“When you start with no knowledge at all, it’s rough,” said Mitch Yergert, head of Colorado’s Division of Plant Industry, an agency within the Agriculture Department that regulates marijuana production.

Yergert conceded that Colorado agriculture officials ignored marijuana entirely for more than a dozen years, from the time voters in the state approved medical pot in 2000 until recreational pot shops started opening in 2014. [Read more at Civilized]