Celeriac

Growing Conditions

Growing Zones

Thrives in USDA Zones 3 - 9

Companion Planting

When to Plant

• Start Indoors

  10-12 weeks before last frost

• Transplant

  2-4 weeks before last frost, once soil is workable and nights stay above 40°F

• Harvest

  Harvest when the crown is 3-4 inches across, typically late September through November; a light frost improves flavor. Twist off outer stalks and cut the root flat; store in damp sand or refrigerate.

Organic Growing Tips

• Side-dress with mature compost or worm castings at the base of each plant midseason to sustain the long growing season without forcing excessive top growth

• Apply a 2-3 inch layer of straw mulch around plants in midsummer to retain consistent soil moisture and moderate soil temperature, which celeriac roots demand

• Water with compost tea every 3-4 weeks during active growth to support soil biology and feed plants without harsh nutrient spikes

• Trim outer leaf stalks that are yellowing or dying back to keep air circulation high and direct energy into crown development

• Avoid high-nitrogen inputs after midsummer; excess nitrogen produces lush foliage at the expense of crown size and flavor

• Allow the crown to experience light frost before final harvest to convert starches and deepen the characteristic nutty flavor

Common Pests

• aphids
• carrot fly
• celery leaf miner
• slugs
• leatherjackets

Taxonomy

Kingdom

Plantae

Family

Carrot family (Apiaceae)

Genus

Apium

Species

Apium graveolens var. rapaceum

Natural History

Celeriac is a cultivated variety of wild celery, Apium graveolens, native to marshy coastal regions around the Mediterranean and into western Asia. Wild celery was known to ancient Greeks and Romans as a bitter, aromatic plant associated with funerary rites and medicinal use; Homer references it in the Odyssey. The swollen-crown form was selectively developed in northern and central Europe during the 16th and 17th centuries, with the earliest clear horticultural descriptions appearing in European herbals of the 1600s. Unlike stalk celery, celeriac tolerates heavier clay soils and stores through winter, making it a staple of northern European kitchens.

Traditional Use

The broader Apium graveolens species, including ancestors of celeriac, was documented in ancient Greek and Roman medical traditions as a diuretic and aromatic plant used in various preparations for digestive and urinary complaints. Medieval European herbalists listed celery-type plants in compilations such as the Capitulare de Villis under Charlemagne and later in herbals by Matthioli. Celeriac itself, as a distinct root form, was less prominent in historical medical literature than its stalk celery relatives.

• Ancient Greek medicine, classical period - leaves and seeds

  Greek physicians referenced selinon, a plant closely associated with the Apium genus, in contexts involving aromatic and cleansing properties, with leaves and seeds noted in dietary and medicinal records of the period.

• Medieval European herbalism, 16th-century Italian herbals - root and seed

  Pietro Andrea Mattioli's 16th-century commentary on Dioscorides described celery-type plants including the swollen root forms then being cultivated in Italy, noting their aromatic seeds and roots in the context of traditional European humoral medicine.

Celeriac and celery family plants contain furanocoumarins, which can cause photosensitive skin reactions in some individuals handling large quantities of fresh plant material. Those with Apiaceae allergies should exercise caution.

This information is provided for historical and educational purposes only and is not medical advice. Always consult a qualified healthcare professional before making decisions related to your health.

Morphology (Plant Structure & Identification)

• Root System

  The edible portion is a swollen hypocotyl and upper taproot forming a dense, globular crown just at or above the soil surface; numerous fibrous roots and lateral shoots emerge from the bottom and sides of the crown and should be trimmed to direct energy into the central mass.

• Stem

  The hollow, ribbed green stems arise directly from the crown and are edible but strongly flavored; they can be chopped and used like celery stalks, though the main crop value is the root.

• Leaves

  Compound, dark green leaves resemble flat-leaf parsley and are aromatic when bruised; yellowing or dying outer leaves indicate nutrient stress or natural senescence and should be removed to improve airflow and discourage fungal disease.

• Flowers

  In its second year celeriac bolts to produce flat-topped white umbels typical of the Apiaceae family; bolting in the first season, triggered by cold exposure of young seedlings, ruins root development and should be prevented.

• Fruit

  Small ribbed seeds form in pairs after flowering; seed-saving from second-year plants is practical for the home gardener, though commercial and F1 varieties may not come true to type.

Known Varieties

Common cultivars worth knowing

• Brilliant

  A widely grown modern variety with a smooth, round crown and white interior that resists browning; relatively fast to mature for the type.

  Best for: General home garden and cooking use

• Giant Prague

  An heirloom variety producing large, somewhat irregular crowns with robust flavor; reliable open-pollinated seed for seed-saving.

  Best for: Heirloom gardens and storage

• Monarch

  A Dutch variety noted for its smooth skin and reduced lateral shoot production, which means less trimming during growth.

  Best for: Growers wanting lower maintenance during the growing season

• Ibis

  An early-maturing variety suitable for shorter growing seasons; produces medium-sized crowns with good texture.

  Best for: Cold climates with short summers