Now becoming popular in the kitchen, celeriac is grown for its mild tasting knobbly roots which have a lovely celery-like flavour and are extremely versatile.
Often grated and added to salads, they are also used boiled or roasted as a hot vegetable, in soups and stews or as a tasty addition to mashed potatoes. It can be used as a general celery substitute and is easier to grow. The leaves can also be used for flavouring, in salads or as a garnish.
Celeriac is a cold season crop so can be started early, ready for harvesting in late summer. The leaves however can be picked earlier, taking just a few from each plant will allow the roots to grown on.
Sow indoors from March to April, thinly in trays of compost, 1.5cm/half-in. deep. Keep at 15-20C/60-68F. Thin out to 5cm/2in between plants. When large enough to handle transplant singly into small pots.
Young plants are planted out at the end of May/early June. They are very sensitive to cold weather at this stage, so should be hardened off slowly over a week or two. Planting out should be delayed if there is still a chance of frost. Using cloches will help warm up the soil before planting and then get them off to a good start. Plant out 30cm/12in. apart in rows 40cm/16in. apart making sure not to bury the crown - the stem base should be at soil level. Water in dry weather and mulch around the plants. Remove any side shoots as they form and from mid-summer onwards remove a few lower leaves to expose the crown. In late September draw a little soil around the swollen stem base to keep it white.
Start lifting from late September/early October. In most areas the roots can be left in the soil until required; cover with straw or compost to protect against frost.