Given the fact that it is legal to grow in some states should questions regarding growing marijuana be allowed?
Our servers are in New York, US, where growing marijuana is illegal. We could get subpoena'd for your information and we'd be forced to give the authorities whatever they asked for. So while our audience is most definitely global, our company and corporation is not.
I don't really think talking about growing marijuana is actually illegal, but I'm not sure you want to start attracting people that were interested in that particular topic because their overlap with expert gardeners and landscapers is minimal.
Given that you could ask pretty much any gardening aspect of marijuana growing question you wanted without actually talking about marijuana (hydroponics on topic, lighting on topic, etc), I think this community would be best served by deciding it's off topic.