How to Grow Celeriac from Seed
Celeriac is a slow-growing root vegetable grown for its large, knobbly bulbs with a mild celery flavour. Starting from seed early gives plants enough time to develop properly before harvest in autumn.
It requires patience, but with steady care you can produce high-quality roots at home.
Quick answer: how to grow celeriac from seed
To grow celeriac from seed, sow seeds on the surface of moist compost, keep them at 18–21°C, and place in a bright location. Keep soil consistently moist, transplant seedlings as they grow, and maintain steady watering throughout the season.
Step-by-step guide to growing celeriac from seed
Step 1: Choose containers and compost
- Use seed trays or small pots with drainage
- Fill with fine seed compost
- Lightly firm the surface
Step 2: Sow the seeds
- Scatter seeds thinly on the surface
- Do not bury deeply — seeds need light to germinate
- Lightly press into the compost
Step 3: Provide warmth
- Keep at 18–21°C for germination
- Use a propagator or warm indoor space
- Germination can be slow
Step 4: Water and provide light
- Mist or water gently
- Keep compost consistently moist
- Place in a bright position once seedlings appear
Step 5: Transplant and grow on
- Prick out seedlings when large enough to handle
- Pot on into larger containers
- Harden off before planting outdoors
When to sow celeriac seeds
Celeriac should be started:
- In early spring indoors
- Early sowing is essential due to slow growth
- Requires a long growing season
Seeds can take 2–3 weeks (or longer) to germinate.
Best celeriac varieties
- Monarch
- Smooth bulbs
- Good disease resistance
- Giant Prague
- Large roots
- Reliable performance
- Prinz
- Compact and uniform
- Good for smaller spaces
Choose based on size, uniformity, and growing space.
Ideal growing conditions
- Temperature
- Moderate warmth (18–21°C early on)
- Light
- Bright light after germination
- Soil
- Rich, moisture-retentive soil
- Water
- Consistent moisture is essential
- Avoid letting soil dry out
Celeriac needs steady conditions to develop good-sized roots.
Common problems
Poor germination
- Cause: low temperature or old seed
- Fix: increase warmth and use fresh seed
Small roots
- Cause: poor nutrition or inconsistent watering
- Fix: improve soil and maintain moisture
Bolting
- Cause: temperature stress
- Fix: avoid sudden cold exposure
Leggy seedlings
- Cause: insufficient light
- Fix: move to a brighter location
Climate and regional notes
UK & Ireland
- Start indoors early for best results
- Needs a long growing season
Europe
- Northern regions require early sowing
- Southern regions may sow earlier
USA
- Start indoors 10–12 weeks before last frost
- Requires steady growing conditions
Pro tips for better results
- Use fresh seed for better germination
- Space plants well when transplanting
- Feed regularly once established
- Keep soil consistently moist
- Remove outer leaves to improve bulb development
FAQs: growing celeriac from seed
When should I sow celeriac seeds
In early spring indoors to allow enough time for growth.
Do celeriac seeds need light to germinate
Yes, they should be sown on the surface.
How long does celeriac take to germinate
Usually 2–3 weeks, sometimes longer.
Why are my celeriac roots small
Often due to poor soil, lack of nutrients, or inconsistent watering.
Can I grow celeriac in containers
Yes, but use deep containers and maintain moisture.
How often should I water celeriac
Keep soil consistently moist at all times.
What soil is best for celeriac
Rich, fertile, moisture-retentive soil.
When can I harvest celeriac
In autumn once roots have reached a good size.
Does celeriac need feeding
Yes, regular feeding improves root development.
How long does celeriac take to grow
Several months from sowing to harvest.