Prop 215 allows you to grow whatever is necessary to suite your medical needs. SB420 gave law enforcement guidelines set forth by the state able to be modified by the county. If you have an Rx you are covered by Prop 215. If you want to make yourself more legitimate...lookup Department of Public Health. They will have a medical marijuana section. This is your best bet to ensuring you have the information to guard your grow. There used to be a limit to the number of plants that a patient could grow, this was part of SB420. That section has been repealed by the CA supreme court as it violates our rights, thus removing the limit. The DEA has a limit set at 99 plants. A plant is considered to have it's own roots and is able to sustain life. Thus a cutting/unrooted clone is not a plant and not the be counted.
I took a class down in Pasadena with MCCDirectory.org. They've got a cultivation class with DJ Short that I may attend soon.