What is Celeriac
This is a variety of celery forming a swollen root which may be used and eaten raw in salads, or cooked for soups and flavoring. The stem can be cooked in the same way as seakale and, unlike celery, it stores well. It grows on the flat and as it requires no trench it is becoming more popular, since there is a great saving in time and labour. It is known botanically as Apium graveolens rapaceum (Umbellifrae).
Cultivation To produce a good crop a long season of growth is needed. Sow in heat during March, prick off into boxes and, after hardening off, plant out in May into well-worked soil at 30-40cm (12-15in) apart. The topsoil should be fine, and mixed with well-decayed manure or spent hops. On light soils, plant in a drill to facilitate watering; planting on a slight ridge is best on heavy soils, to improve drainage. The swollen root must be planted so that it sits on the soil and must remain so throughout its growth. As it matures it may be necessary to draw soil away from it, until protection from frost is required. Water copiously and apply 14g (1oz) of nitrate of soda to each 2m (6ft) stretch of row if the plants are slow in making early growth. Remove any sideshoots and suckers from the root. The variety `Giant Prague' is good, but 'Marble Ball' stores extremely well.