God damn it. I wrote a nice long response and it timed out.
Long and short of it. Your landlord has to give you 48hour written notice to inspect the property. That is the law and I am well aware of tennant law as I own two rental houses. One in WA and one in OR.
Here is the bottom line dude. Your pretty much fucked and quite honestly, dilusional if you think this is going to work.
Your landlord or son is going to smell weed, recall you didn't want to be inspected and end up calling the police and or fire marshal to come and inspect the property. Guess what, they don't have to give shit for notice except come between 8am and 7pm. So your going to get forcibly evicted and bonus...growing marijuana for recreation is illegal in the state of Washington so you will be facing criminal charges
And for what...a couple plants you have in some Mickey Mouse grow set up?
Sorry to harsh your mellow, but that is the reality of the situation. Do as you please and best of luck.