Wash your celery and pat it dry. Then wrap it up tightly in foil. For some reason, it keeps it really fresh. And I don’t even much like celery anyways, so I definitely never use a whole bunch of it. It is cheap, but I hate to throw away anything and this trick has saved me from having to chuck old celery.
These pictures are celery that is AT LEAST 2 weeks old. And I’m sure that’s just me being generous because I think it’s a bit older than that. But it’s still crisp, green and fresh. Except a little towards the ends of the stalks, but still!