What you call pharmaceutical production, looks a lot like gardening. An extra child hanging out could be an illegal day-care operation. I few too many boxes could be an untaxed ebay business. The magazines in the gun safe might hold too many bullets. The quantity of Roundup in the garden shed may exceed regulations. Heck, a lot of states still have sodomy laws; are you going to report the lube in the nightstand?
Bingo! Unless I were to witness child, elder, or other domestic abuse, or undisputable evidence of the manufacture and sale of hard drugs, or obvious mold/mildew-related damage or fire risk to the property from the grow, what someone does in their home is simply not my business. How something impacts the condition and marketability of the property might, but growing three-to-six plants of the same flora that the Founding Farmers did is not going to impact the property.
To the OP: To most Oregon appraisers, your situation is old news and a non-starter; sadly, some appraisers here are of the ilk who want to impose moral judgment on your real estate. I feel it's reasonable to disclose the grow and permit to the appraiser, then state that while you expect him to describe the improvements (enclosed room) in the report, you are requesting he not violate your privacy by disclosing the contents or photographing them. One of the social problems with legal medical marijuana grows is that if the local criminal element learns of it, they may try to break in and steal it.
Similar concerns are expressed to appraisers by many homeowners with other types of valuables or homes businesses. I recently appraised the home of an extreme right-wing and privacy/conspiracy nut who was literally paranoid about the photos of the interior of his home being "imbedded" on the internet. He also had artwork he claimed was collectable, so I took pictures from specific angles of his living room, kitchen, and baths, and simply disclosed that interior photos were limited in the report due to borrower's request for privacy. I have had the same experience to a lesser degree of paranoia when homeowners were part-time gun dealers, jewelry-makers, etc. Then there was that couple who sewed leather and latex fetish wear and sold it online-- she kept him in a collar! Again, their business, not mine.
Finally, just make sure the appraiser's name is not Pat "Self-Appointed Vice Inspector/Enforcer of All Federal Statutes/DEA Informant Wannabe" Butler. You might even ask the appraiser their party affiliation before you let them in. Wait, nevermind, a true conservative would support state's rights over federal mandates, especially when it comes to what you can do in the privacy of your own home.