Medical Marijuana. Yes, definitely a question we are asked with frequency in Mendocino County. I understand this question was posted over a year ago, but I think there are others out there who would like a general answer. Basically, although the county and state allow medical marijuana growing and usage with many conditions, it is still a Federal crime-- please remember that.
With that said, my suggestion would be to look for a geographic location with enough land and room between neighbors-- or, if growing indoors, a building or room suitable for that use and with a filtration system to not become a nuisance to the neighbors. Being friendly and considerate with those who live around you can go a long ways to a peaceful existence.
There are areas that are not friendly for growing Medical Marijuana, like in the Willits or Lakeport city limits. The Mendocino County Sheriff's Dept has a program you can register through, too. Always check the location and possible restrictions on the property you may want to purchase.
Also, when looking for ANY property. Ask about water. Does it have a well, district water, spring, etc? A low producing well is not always bad if it is consistent, even in drought years... a spring can be wonderful, but also can stop in the summer months. Years ago when the market was hot, many people forgot to ask important questions like these about the property.
Finally, ask yourself how you are doing to purchase the property? With a conventional loan, private money loan, seller carry-back, or a lease-option? The lease option has become a popular choice, but few know the risks to both buyer and seller. If you do not fully understand the details and risks of a lease option, then you may truly lose out on many thousands of dollars-- so check into that option carefully! With seller financing, the buyer can save because they are not spending money on lending fees-- but the terms including interest rate may not be good for the buyer, and there are also many details about seller financing that should be addressed... and if not, it can cause problems again for both buyer or seller down the road.
Basically, make sure everything is spelled out-- and never feel there is a silly question that you should not ask. There are no stupid questions! Well, almost never! But you get the idea :)