We were always buying the big bags of celery available at Costco but rarely finishing it before it went soft and brown. Eventually we figured out that wrapping the chopped and cleaned celery in foil would help it keep in the fridge for up to a month so now we always have a supply on hand.
Here are some how-to’s we have found that show you exactly what to do.
Keep Celery Fresh For Weeks on Instructables.
RVgeeks tips on YouTube for how they keep celery fresh:
And here is a list of recommended storage methods for celery and other vegetables.