Richmond is now an open city for marijuana cultivation on an industrial scale. The precedent was set by an industrial grower in a M-1 zoned district across the street from an elementary school.
Richmond has a generous marijuana ordinance that allows six dispensaries but under an extensive set of rules. Among other things, the ordinance requires that:
7.102.110 Prohibited activity:
A. It is unlawful for any person to cause, permit or engage in the cultivation, possession, distribution, exchange or giving away of marijuana for medical or non-medical purposes except as provided in this chapter,
B. It is unlawful for any person to cause, permit or engage in any activity related to medical marijuana except as provided in this chapter and in Health and Safety Code Sections 11362.5 et seq., and pursuant to any and all other applicable local and state law and pursuant to any and all other applicable local and state law.
J. No medical marijuana collective shall possess marijuana that was not cultivated by its management members or members either at the property or at a location fully documented and inspected in accordance with this chapter.
Agriculture is not allowed in M-1 zones in the City of Richmond, and the courts have upheld city’s authority to regulate medical marijuana, including banning dispensaries altogether.

Recently, complaints were made about industrial scale growing operations in M-1 zones. There was a concern that the higher rents associated with marijuana growers were driving out legitimate businesses who could no longer afford them and that the locations were for closer to schools and parks than allowed in Richmond’s ordinance, (“…a minimum of one thousand five hundred feet (1,500') from any public or private high school and a minimum of five hundred feet (500') from any park, community center, youth center, public or private child-care center, nursery school, kindergarten, elementary, middle or junior high school”)
Apparently, the growers have produced some notes from doctors stating amount of plants being grown in various "rooms" are appropriate for "patient's medical needs." That is apparently being interpreted as a free pass by Contra Costa District Attorney Mark Peterson, who reportedly refuses to prosecute, and the City of Richmond is so far reluctant to bring a civil action to enforce its own ordinance.

So for now, anything goes. Welcome to Richmond.