Create a list of all the processes you want to standardize. It might be helpful to begin from the initial planting or cloning activity and move your way up the growth phases into harvest, drying, packaging and sale. Seed to sale workflows can be complex. So be precise and detailed in your recording of the steps.
You can also create SOPs by department if that makes more sense for your cannabis business. The propagation team could create their own set of SOPs, veg and flower managers could author cultivation SOPs, and the compliance team could create compliance SOPs for auditing, reporting and cannabis inventory control.