So on the 1001 opposite Krungthai Bank, outside Maejo Uni, is a little stall that opens around 8am and will sell you (a maximum of) five Cannabis seedlings for Bt30 piece.
No other details such as plant gender, whether there are any checks or anything. I'm waiting for everyone to pile up there this morning since someone posted it in one of the expat groups yesterday.
Added: But now you can't because some uppity Thai assaulted a police officer because they ran out.
Maejo University Temporarily Stops Selling Marijuana Seeds After Hot-headed Man Hurts Officers Because He Can't Buy Them In Time For Someone Else - RAJACREATOR
I wonder how many people are going to find that out the hard way this morning?