Celeriac, also called turnip-rooted celery, knob celery, and celery root, is related to and resembles celery. The edible portion is the swollen, knobby stem that forms at and beneath the soil surface. At its best edible size with trimmed roots, celeriac measures from 3 to 4 inches across, and 3 inches long. The interior is smooth and white, similar to kohlrabi or turnip root. The celery-like leaves and stalks are hollow and not very palatable.
'Prague' is the leading variety; 'Delicacy' is also grown. In Florida, neither celeriac nor celery is often grown in gardens because of their requirement for abundant soil moisture for seed germination and subsequent plant growth. Overhead sprinkling on sandy soil, which is a common gardening practice, is not adequate for good celeriac production.
Like celery, celeriac is a cool-season crop that should be seeded in August-December and transplanted through February in Florida. It should be cultivated and cared for in much the same fashion as celery. Seed should be planted shallowly (1/8 to 1/4 inch) and protected from the sun with a shade cover.
Celeriac should last 3 to 4 months when stored at 32 to 40°F and under moist conditions. Celeriac may be used raw or fresh. Since it has the celery flavor, it is often used as a flavoring in soups and stews. It is best to peel celeriac before cooking to remove the tough, stringy outer skin.