Celeriac is a useful substitute for celery for cooking and one that will grow in poorer and drier soil. Seeds should be sown in a cool greenhouse or frame during March or. early April and seedlings hardened off for planting out in May.
Choose an open site and dig the soil well, enriching with manure if possible. Plant 1 ft. apart in rows 18 in. apart. No earthing up is required. Roots can be lifted in October and stored in sand or ashes in a shed. Giant Prague is a good variety.
Celeriac is a variety of celery forming a swollen root which may be used and eaten raw in salads, or cooked for soups and flavouring. 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 (Umbelliferae).
To produce a good crop a long season of growth is needed. Sow in heat 2 during March, prick off into boxes and, after hardening off, plant out in May into well-worked soil at 12-15 inches 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 oz. Of nitrate of soda to each 6 foot stretch of row if the plants are slow in making early growth. Remove any side-shoots and suckers from the root. The variety ‘Giant Prague’ is good, but ‘Marble Ball’ stores extremely well.