It takes approximately three to 11 stalks of celery to make 2 cups, chopped, depending on the size of the stalks. The largest celery stalks typically measure 11 to 12 inches long, medium stalks measure 7 to 8 inches and the smallest stalks measure 5 inches.
Whole stalks of celery can be stored in the refrigerator for up to two weeks when stored in an airtight container with water or wrapped in a moistened paper towel and then placed in a plastic bag. Celery can also be frozen for up to a month without blanching and for up to 12 months if it is blanched first. Because celery turns soft after freezing, such celery is best used in soups, stews or casseroles.