Step-by-Step Growing Guide
Celeriac (Apium graveolens var. rapaceum) is a slow-maturing, cool-season crop requiring 100–120 days from transplant. Start seeds indoors 10–12 weeks before the last frost — celeriac has one of the longest indoor lead times of any vegetable. Sow seeds very shallowly on the surface (they need light to germinate) at 18–21°C soil temperature. Transplant after the last frost into very rich, moisture-retentive soil with a pH of 6.0–7.0 that has been heavily amended with compost. Space 30–35 cm apart in rows 45 cm apart. Water frequently and consistently — celeriac is extremely drought-sensitive and any dry period causes woody, cracked roots. Feed every 2–3 weeks with a balanced liquid fertiliser high in nitrogen early in the season. From midsummer, remove side shoots and the lower leaves to expose the developing swollen root to air and light, which improves surface finish and size. Celeriac tolerates light frost and flavour improves after cold exposure.