Celeriac Growing Guide
Celeriac, looking like a pale, knobbly swede, is a tasty, extremely hardy crop for colder months. Its edible part is a swollen stem with a mild celery flavour, rich in nutrients, antioxidants, and fibre. It can be grated raw into winter salads, cooked and mashed like potato, added to stews and soups, or sliced and roasted.
This guidance applies to the crop in general. Individual varieties and local conditions can differ.
Planting information
Start seeds indoors in March in peat-free seed compost, covering lightly. Keep at about 15°C for germination, which can take three weeks. Move seedlings into bright light and keep above 10°C to reduce bolting. Water regularly, thin modules to one seedling and pot on when large enough to handle. Harden plants off before transplanting in late May or early June, after frost risk has passed; delay during cold weather. Use the variety guidance for cultivar-specific timing and spacing. The general crop layout is 30cm between plants and 40-45cm between rows. Enrich the bed with compost beforehand and keep the crown at soil level. Water plants in; fleece or cloches can provide early protection. Keep soil consistently moist without waterlogging, and mulch to conserve moisture. Apply liquid feed during summer, following the product instructions. Wear gloves when handling foliage. As the crown becomes visible, remove side shoots from its sides while retaining the main upright growth.
Harvesting information
Harvest celeriac from October through to the following March. It is hardy and can usually be left in the ground until required, developing a stronger flavour over time. Carefully ease individual plants out of the soil with a fork. In colder sites, spread a thick layer of straw around plants to prevent the soil from freezing. To prepare, remove the small roots and the often knobbly outer skin. Celeriac can grow quite large without turning woody. Excess can be blanched and frozen.
Storage information
If not harvested by spring, plants can be lifted and transplanted into spare ground or stored. To store, twist off the leaves, then place the celeriac in a container of peat-free potting compost or coir in a cool shed or garage. If you have heavy soil or the site is prone to winter waterlogging, dig up and store celeriac in late autumn. Excess can be blanched and frozen.