The bleaching celery that is not consumed in autumn is felled in the cellar before the onset of frost.
By harvesting and consuming the celery, you can do about 3 weeks after wrapping begin. Frost renders the petioles unusable. That's why you take out the remaining plants with their roots and wrap them up in damp sand or earth in the basement. The basement must be airy, so that the wrapped stems do not harden. When the basement is completely dark, the covers can be removed.