I don't know how long celery will last sitting in an open container full of cold water like that, but it lasts the 2-3 days it takes me to eat all of the celery.
When I go looking in the fridge I see the peanut butter and then the celery, it only takes a couple of minutes to put some peanut butter on a few stalks on a plate. It probably takes less time than it does to cook a hot pocket or something along those lines.
Here's a photo with the last few pieces left.
celery.jpg [ 23.35 KiB | Viewed 2146 times ]