Repotting guide

When & how to repot Celeriac 'Prinz' (Apium graveolens var. rapaceum 'Prinz')

Also called Prinz celeriac, turnip-rooted celery.

More about celeriac 'prinz'

About Celeriac 'Prinz'

Apium graveolens var. rapaceum 'Prinz' · also called Prinz celeriac, turnip-rooted celery · edible

'Prinz' is a refined celeriac valued for smooth, well-rounded swollen stem-bases, white flesh that resists discolouring, and good bolting resistance. A long-season crop needing 100-120 days, it is started indoors in early spring, planted out after frost, and lifted in autumn. It demands rich, constantly moist soil and steady feeding to size up well.

Mature size: Foliage 30-45 cm tall; swollen crowns typically 8-12 cm across, around 0.5-1 kg.

Watch for — Celery leaf spot (Septoria): Brown spotted lesions on leaves spread in wet weather and from infected seed. Use treated seed, water at the base, and space plants for airflow.

How to tell celeriac 'prinz' needs repotting

Repotting on a calendar is less reliable than reading the plant. For celeriac 'prinz', watch for these signs:

Roots circling the bottom of the module or pot, or poking out of the drainage holes.
The seedling dries out within a day and growth has visibly stalled.
Roots are white and matted in a tight spiral when you tip the plant out.
It has outgrown its current container for the stage of the season — pot celeriac 'prinz' on before it becomes hard root-bound.

For the underlying biology of a pot-bound root system and why it stalls a plant, see our guide to spotting and fixing a root-bound plant.

How often to repot celeriac 'prinz'

Pot on seedlings as they grow; not a perennial repot. Celeriac 'Prinz'is grown for one season, so the question is really “how often to pot on” — keep moving it up before the roots circle. Biennial grown as an annual, forming a tuft of celery-like foliage above a swollen, knobbly stem-base (the edible 'root'). Bolts to flower in its second year, or in its first if checked by cold or drought..

What size pot to step celeriac 'prinz' up to

Pot celeriac 'prinz' on gradually — a seedling jumped straight into a huge pot sits in cold, wet, airless soil and stalls. Step up one or two sizes at a time as the roots fill each container, finishing in a large final pot or the ground. The aim is roots that never circle and never check.

Not sure of the exact diameter? Our pot size calculator takes the current pot and root spread and tells you the right next size — it deliberately recommends a single step up, never a big jump.

The best time of year to repot celeriac 'prinz'

Pot celeriac 'prinz' on through the active growing season, whenever roots fill the current container — there is no single date, just "before it becomes root-bound". Avoid potting on during a cold snap.

Step-by-step: repotting celeriac 'prinz'

Pot on before it is root-bound. Check celeriac 'prinz' regularly; move it up as soon as roots reach the edge of the cell or pot, not after they have circled.
Step up one or two sizes. Choose the next container up — not a giant one. Cold, wet, unused soil around a small root system stalls seedlings.
Knock it out gently. Support the stem, tip the pot, and ease the rootball out without breaking it. A little teasing of circled roots at the base is fine.
Pot into rich mix. Set it into fresh rich, moisture-retentive loam high in organic matter, ph 6.5-7.0 at the same depth (tomatoes are the exception — they can go deeper to root along the stem).
Water in and grow on. Water well, keep it in good light, and resume feeding once it is established and growing again.

Aftercare

Water celeriac 'prinz' in well and keep it in bright light; a freshly potted-on seedling can wilt for a day while roots settle, so do not overcompensate by drowning it. Do not fertilise for about 1 week — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for celeriac 'prinz'

Celeriac 'Prinz' wants rich, moisture-retentive loam high in organic matter, ph 6.5-7.0. Wants deep, fertile soil enriched with plenty of well-rotted compost to hold moisture. Poor, dry, or thin soils give disappointing crowns. Keep the swelling crown at the surface, removing side-shoots and lower leaves late in the season. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting celeriac 'prinz' — frequently asked questions

How often should you repot celeriac 'prinz'?

Pot on seedlings as they grow; not a perennial repot for celeriac 'prinz'. Celeriac 'Prinz' is a seasonal crop, so you pot it on as a growing plant rather than repotting a perennial. Step seedlings up gradually into rich, moisture-retentive loam high in organic matter, ph 6.5-7.0 so the roots never circle the cell, ending in a large final container. A root-bound transplant stalls and never fully recovers.

What size pot does celeriac 'prinz' need?

When is the best time of year to repot celeriac 'prinz'?

Can you put celeriac 'prinz' straight into a much bigger pot?

No. Even a fast-growing celeriac 'prinz' should only go up one pot size at a time. A vastly oversized pot holds a reservoir of wet soil the roots cannot reach, which stays cold and soggy and rots the roots — the opposite of what you wanted.

Should you fertilise celeriac 'prinz' after repotting?

Not immediately. Wait about 1 week after repotting celeriac 'prinz'. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.