Celeriac
Apium graveolens var. rapaceum
Celery flavour in a storable root, and it needs the entire season to get there.

Start very early indoors
Celeriac needs the longest season of the common root crops. Sow indoors ten to twelve weeks before last frost. Seed is tiny and needs light to germinate, so press it onto the surface rather than covering it, and keep it consistently moist at around 70F. Germination is slow.
Never let it dry out
Like celery, it is a marsh plant at heart. Any drought check gives a small, woody, hollow root. Consistent moisture is the single most important factor - mulch heavily and water deeply in dry spells.
Rich soil
Heavy feeder. Work in generous compost and side-dress with nitrogen every four to six weeks through the season. Poor soil gives a knobbly little root not worth the space it occupied all year.
Strip side roots and lower leaves
From midsummer, remove the side shoots and the upper side roots that form around the crown, and take off the lower leaves. This produces a rounder, smoother, easier-to-peel bulb rather than a knobbly mass.
Do not hill it
The swollen part sits at soil level and should stay exposed. Burying it encourages more side roots and rot.
Pests and disease
Celery leaf miner blotches the foliage; row cover prevents it. Slugs shelter in the crown. Septoria leaf spot causes small brown speckles in wet weather and mostly costs you foliage rather than root.
Harvest
Lift before the ground freezes hard, when roots are three to five inches across. Frost improves the flavour, so there is no hurry until a hard freeze threatens. Trim the roots and tops, and expect to peel thickly - the skin is gnarled and there is no way around some waste.
Storage and use
Keeps three to four months in damp cold storage or in a perforated bag in the fridge. Raw it is excellent grated into remoulade; cooked it purées and roasts well and gives soups the celery flavour without the strings.
- Days to harvest
- 100-120
- Start indoors
- 10-12 wks pre-frost
- Spacing
- 8-10 in
- Row spacing
- 18-24 in
- Sun
- Full
- pH
- 6.0-7.0
- Water
- Constant
- Storage
- 3-4 months