It's tempting to buy the big bag of celery at the supermarket, but you'll seldom use it all by the time it starts to fade. If you wrap the celery in a plastic bag and then wrap that bag in aluminium foil you can get a much longer refrigerated shelf life.
Prepper weblog Preparing One Day at a Time claims they've kept celery fresh using this technique for more than a month. I can't verify that as of right now, but next time I go to the supermarket I'm going to give it a try.
What methods do you use to preserve produce in your fridge? Let us know in the comments below.