I agree on the home growing comment as well. The author equates growing at home to mixing your own prescription drugs and such. I would equate it to making your own wine or alcohol for personal use. While there may be a knack to it - it is not rocket science.

Further I would add while this may be an option for some, I would expect most people to purchase from a store for its convenience and quality. Much the same way most people purchase alcohol from a store.