How to grow Celeriac
Updated October 2026
Celeriac, also called celery root or knob celery, is a form of celery grown for the knobby, celery flavored root that swells at the soil line. It is a long, slow cool season crop, taking around 200 days from seed, and it needs steady moisture all the way through. Its flavor is best after the first fall frost, and roots can stay in the ground under mulch to be dug through winter in many areas.
📖 Our full guide: How to Grow Celeriac
Not to be confused with: Celeriac is the same species as celery but bred for its root rather than its stalks.
Where to plant
Grow celeriac in full sun in a rich, moist, well drained loam with plenty of organic matter. It is a cool season crop, and long spells below about 55°F (13°C) while plants are young can make them bolt, so protect early transplants with covers in cold spells.
Because it needs a long, cool season, timing depends on region. In Florida, the Gulf South, Texas, the desert and Southern California, set transplants out in fall for a winter and spring harvest. In the Mid-South, plant in April or in August for a fall crop. Across the North, the Midwest, the Mountain West, the Pacific Northwest and Alaska, start seed indoors 10 to 12 weeks ahead and plant out once after the last frost, for harvest in fall.
Choosing a variety
The University of Arkansas lists Giant Prague (also sold as Prague or Large Smooth Prague), a large, round, smooth skinned root that stores well, Monarch, with smooth, cream colored roots, and Brilliant, with 3 to 5 inch roots that store well.
How to plant
- Sow seed a quarter inch (6 mm) deep or less on moist seed starting mix, indoors 10 to 12 weeks before planting out. Germination is slow and can take three weeks or more.
- Grow seedlings on in a bright, cool spot and pot them up as they grow. Keep the mix evenly moist.
- Harden off and plant out after the last frost, at the same depth they grew in their pots, about 6 to 12 inches (15 to 30 cm) apart in rows 18 to 24 inches (45 to 60 cm) apart.
- Water in with a dilute starter fertilizer to get them established quickly.
Watering and feeding
Water evenly and often, especially in dry weather. The University of Arkansas notes any interruption in growth seriously reduces root size. Mulch around the plants to keep the soil cool and moist.
Celeriac is a moderate feeder. Dig in compost before planting and feed lightly about once a month through the season.
Pruning and care through the year
- As the roots swell, pull off the lower side leaves and any small side shoots around the top of the root to keep it smooth.
- Draw a little soil up around the swelling roots to keep the flesh white, as the University of Arkansas suggests.
- Weed carefully by hand; the roots sit at the surface and are easily damaged by hoeing.
- Cover young plants on nights well below 55°F to reduce bolting.
Harvesting
Roots are edible at any size but are best at about 3 to 4 inches (8 to 10 cm) across, about the size of a baseball. Flavor improves after the first fall frost. Loosen the soil with a fork, lift the root and trim off the leaves and the tangle of fine roots. The leaves can be used like celery leaves.
In many areas you can leave celeriac in the ground under a thick mulch of straw or leaves and dig it as needed through winter. Varieties such as Giant Prague and Brilliant store well after lifting if kept cold and humid. Peel the brown skin before using the white flesh raw in salads or cooked in soups, stews and mash.
Companion planting
Celeriac suits a bed of other slow, moisture loving crops.
Good companions
- Leek Another slow, upright crop that likes the same moist, rich soil.
- Beans Bush beans can share the bed in summer without shading the celeriac.
- Brassicas Share the cool season and rich, moist soil.
Keep apart
Avoid planting these close to celeriac.
Pests and diseases
The leaves and stems are generally free from pests; slugs on young plants and leaf diseases in wet weather are the main problems.
Pests to watch for
- Slugs and snails Holes in young leaves and grazed stems in damp weather.
Diseases to watch for
- Leaf spot Brown spots on the leaves in wet weather; water at the base.
- Sclerotinia White mold: soft, rotting stems with white cottony growth near the base in cool, wet weather.
Common questions
How long does celeriac take to grow?
About 200 days from seed, which is why it is started indoors 10 to 12 weeks ahead. The University of Arkansas notes the root is edible at any stage, so you can harvest small ones early.
Why is my celeriac root small?
Any check in growth, from dry spells, crowding or poor soil, seriously reduces root size. Keep watering steady, feed lightly and give plants room.
When do I harvest celeriac?
When the roots are about 3 to 4 inches across, ideally after the first fall frost, which improves the flavor. In mild areas, leave them in the ground under mulch and dig as needed.
Why is celeriac seed so slow to germinate?
Celery family seed is naturally slow, often taking three weeks or more. Sow it shallowly, keep it constantly moist and warm, around 60 to 70°F.
Can I grow celeriac in Florida or Texas?
Yes, as a fall planting for winter and spring harvest, when the weather is cool. It struggles in summer heat.
How do I prepare celeriac?
Cut off the knobbly brown skin and use the white flesh grated raw in salads, or cooked in soups, stews and mash.
Sources we checked: University of Arkansas FSA6080: Home Gardening Series, Celeriac; Cornell Home Gardening: Celeriac growing guide; Utah State University Extension: How to Grow Celery in Your Garden.
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