Yeah I somehow got over that by going to the washroom in my house and filling it with you know what. But later in the quest when we have to cut the tendrils another issue arises where we can't pick anything up from the medical supplies to feed the hungry tendrils.
I remember completing this quest before so I think it's just native to this version. So I am trying to install another version move the save files there complete the quest and then return to this version let's see if that works.
I found a way to complete it after a couple of tries. I suggest reloading a save right before you water the tree for the first time (basically starting the quest), then go to the nurse office and take the medical supplies. Also if you don't have a water bottle on you make sure you buy one or take one from the kitchen, because you need it for the last vine. So don't use it to water the tree a second time use the workaround you mentioned. Hope this helps.
Ah I'm guessing Isabelle is knocking on the door, you can skip that part by choosing the option "freeze in place" or something like that. Forgot about that part. The official in-depth walkthrough mentions that part too and explains how you can get past it without having to talk to her. So I'm assuming you mean that part.
