Celeriac is a cool-season biennial grown as an annual. It is similar in growth habit and requirements as celery. Celeriac is best when it comes to harvest in cool weather. It is best started indoors and later transplanted into the garden. Sow seed indoors as early as 10 weeks before the average last frost date in spring. Celeriac requires 90 to 120 days to reach harvest.
Description. Celeriac is grown for its large, swollen root that looks something like a turnip. The root develops at soil level similar to a turnip but celeriac is a member of the celery family and has a similar growth habit. From the root, a rosette of dark green leaves sprout atop hollow stems.
Yield. Grow 2 to 3 celeriac plants per household member.
Site. Celeriac grows best in full sun but will tolerate light shade. Plant celeriac in moisture-retentive but well-drained soil rich in organic matter. Add aged compost to planting beds before plants and again at midseason. Celeriac is a heavy feeder; give plants a side dressing of compost tea every 2 to 3 weeks during the growing season.
Planting time. Celeriac grows best in cool weather, especially where nights are cool. Grow celeriac in spring in cold-winter regions; in warm-winter regions grow celeriac beginning in late summer so that it matures in cool weather. Celeriac is slow to germinate and is best grown from transplants. Sow seed indoors as early as 10 weeks before the average last frost date in spring. Plants can go into the garden on the average date of the last frost. Celeriac requires up to 120 days to reach harvest. A late summer crop can be sown directly in the garden where there is enough time for a second harvest.
Planting and spacing. Sow celeriac seed ⅛ inch deep. Place a seed cloth or burlap over the seeding area to keep the soil moist until plants sprout. When plants are 3 to 4 inches tall thin them from 6 to 8 inches apart or transplant them into the garden at that distance. Space rows 24 to 30 inches apart. Celeriac is often set into the garden in 3- to 4-inch deep trenches, similar to celery. As the plants grow, soil can be mounded around the exposed root.
Companion plants. Lettuce, spinach, English peas. Do not plant celeriac with pumpkins, cucumbers, or squash.
Container growing. Celeriac can be grown in a container, but not well. Choose an 8-inch container for a single plant.
Caring for Celeriac
Water and feeding. Celeriac is shallow-rooted and requires regular watering. Lack of soil moisture will cause celeriac to stop growing. Keep the top few inches of soil moist at all times.
Care. Keep celeriac planting beds weed-free to avoid competition for water and nutrients. Cultivate carefully to avoid celeriac's shallow roots. As the root develops, snip off the side roots and hill up the soil over the swollen bulbous root to blanch it. The outside of the root will blanch white but the flesh will remain a brownish color.
Pests. Celeriac has no serious pest problems.
Diseases. Celeriac has no serious disease problems.
Harvesting and Storing Celeriac
Harvest. Harvest celeriac when the swollen root is 3 to 4 inches across or slightly larger. Cut stems close to the knobby root; use a garden fork to lift the roots. Celeriac will increase with flavor following a light frost but should be harvested before the first hard freeze. Leaves can be used to flavor soups and stews. From seed, celeriac will reach harvest in 110 to 120 days.
Storing and preserving. Celeriac will keep in the refrigerator up to one week, or store the root in a cold, moist place for 2 to 3 months. Celeriac will keep in the ground where the soil does not freeze. Leaves can be used as an herb in soups and stews.
Celeriac Varieties to Grow
Varieties. ‘Alabaster' (120 days); ‘Giant Prague' (120 days).
Common name. Celeriac, turnip-rooted celery, celery root, knob celery
Botanical name. Apium graveolens rapaceum
Origin. Europe and Africa
Grow 80 vegetables: THE KITCHEN GARDEN GROWERS' GUIDE