If you are under a lease you will retain many more rights then renting month to month. I have seen the issue argued many times from the sidelines. The most effective course of action is to
1- have the garden clean
2- in a tent or grow space never attach anything to the structure if possible use an L brace from either side and you have a free standing partition, which is not altering the structure.
3- A real electrician needs to come in on your dime and make sure the wiring is up to code and safe, have him leave a reciept showing this was done, he will need to look at your grow equipment most likely as well.
4- thick plastic between the garden and any woodfloor/carpet , and the number one complaint.... humidity they will suggest your causing black mold we used filters to argue we were running clean.
5- if its medical and you are the patient insist on a reasonable medical allowance this really works way more often then you would believe.
6- be polite its just thier responsibility to check on the property, they are people too talk to them perhaps a non refundable deposiit for any damages that you might incur +this is usaully known as a bribe
7- Understand you have a medical issue that is not thier business and you do not have to divulge the fact you are gonna grow pot there before moving in, even though finding a pot friendly landlord is kewl many of the things people are worried about are discriminations when it is applied to any other situations. Don't let them scare you there are provisions in the law within Oregon at least that you cannot be evicted for providing yourself with the medicine. being sick doesn't make you a second class citizen. If you have been treated this way I highly suggest speaking to a lawyer. When I explained a similar problems my lawyer gave me a high five because they are screwed for being bigots.
Still living there and now he says I am the best tenants he has ever had. Mostly because i pay rent on time lol.