Use fresh seed as the capacity to germinate decreases rapidly and sow from March to May. Germination can be erratic so it is best to sow 2-3 seeds in stations 1-2cm (¼-¾ in) deep, 10cm (4in) apart, with 30cm (12in) between rows.
When seedlings are large enough to handle, thin to leave the strongest seedling. Alternatively, sow in rows, thinning to the correct spacing.
Grow in open, light, well-drained, stone-free soil, manured for the previous crop and carefully forked over in the case of heavier soils.
Keep weed free, hand weed to prevent damaging the roots, using an onion hoe with care, or mulch to prevent weed growth.
Bolting: Plants flower and set seed prematurely.
Remedy: Unless growing for seed sow bolt-resistant varieties. Sow or plant at the correct time and keep the soil or compost moist.
More info on Bolting
Lift roots very carefully, easing them out with a fork, as they snap easily and bleed if cut. Harvest from late September onwards.
Protect top from frost with straw, bracken or similar materials or, in very cold regions or where the soil is prone to waterlogging, lift and store roots in sand or sawdust and overwinter in a cool, frost free garage or cellar.
Roots can be left in the ground to produce edible shoots the following spring.
Cut back old leaves to within 2.5cm (1in) of the soil and 'earth up' to 12.5-15cm (5-6in), from April to May, and harvest the blanched shoots as they appear, clearing the surrounding soil away carefully.
On heavier soils, blanch new growth with bracken, straw or something similar when new growth appears in spring. An upturned bucket can also be used.
Leaves can be cut when 15cm (6in) tall, without blanching but are not as tender.
'Sandwich Island':Has strongly flavoured roots and smooth skin.
'Geante Noire de Russie':An extremely long, black skinned variety with a superb flavour.
'Giant':A consistently long rooted variety.