you say you've been single forever then suddenly this girl pops up? hmmm could be a coincidence, or it could be the weed god testing your loyaltie's, or it could be a government infiltrator that has read what your doing here? I wonder what the correct answer is ??????????

Lol I see no real reason she has to know, if you live by yourself, throw an old mattress and some clothes in a bedroom and tell her you have a roomate, but he's a truck driver and is gone all the time. In the mean time unless she moves in with you she'll have no reason to go into the basement, just dont give her any keys. I see no problem there, also (just in case) you can hang up a noose next to your grow just in case there are any (unseen) consequences, Have an emergency grave dug (just in case) hide it with plywood over the top covered with a thin layer of dirt and leaves.