Step-by-step Guide to Growing Seakale
Crambe maritima (fam. Cruciferae)
Sowing to harvesting time: 2 years if sown from seed.
Planting to harvesting time: 10-12 months if grown from root crowns
Size: plants grow to about 45 cm (1-½’); blanched shoots cut when they are about 18-23 cm (7-9”) tall.
Yield: 450 g (1 lb) per plant
The nutty, slightly bitter, blanched young shoots ofare a delicacy which is undeservedly rare. These blanched shoots are produced by covering the plants in the winter after the summer foliage has died down. They can be boiled and prepared in a similar way to asparagus and some people rate them as highly, yet they are as easy to grow as . Moreover, they are ready in the early spring when few other vegetables are available.
Seakale is one of the few vegetables native to Western Europe and Britain, and still grows wild along the coast in some places; this wild seakale can be made to produce blanched shoots by covering it with shingle. In the garden the plants are more usually covered with buckets and leafmould outdoors, or forced indoors in boxes to produce an early crop.
Seakale can be raised from seed but if this is done it takes two years to produce edible shoots. Most people, therefore, either put in ‘planting crowns’, obtained from a nursery, or use ‘thongs’, ie.. If these are planted in the spring, the delicious young shoots should be ready for eating in the following spring.
Suitable site and
Seakale is a native of the seashore and prefers an open site and a sandy, well-drained soil. Nevertheless, it will grow in most gardens, provided they are not heavily shaded.
Dig the soil in the autumn, adding sand to lighten it if it is heavy. In addition, add manure at the rate of one 9 L (2 gal) bucket per sq m (sq yd). The best manure to use is composted or fresh seaweed, but if you cannot obtain any of this, use well-rotted farmyard manure or gardeninstead.
Seakale dislikes acid soil. A few weeks after manuring test the soil with a soil test kit and add carbonate of lime, if necessary, to produce a pH of about 7.0.
Although not as permanent as an asparagus bed, for example, you can expect to leave a seakale bed in the same position for several years. Therefore choose an open site where a permanent bed will not get in the way of your other crops.
Seakale is not often grown from seed because it takes two years to produce a crop if grown this way. Moreover, seakale does not always grow true from seed. Seed-grown plants may vary in colour, or not respond properly to forcing. Nevertheless, if you are patient, and discard the less vigorous and badly or abnormally coloured plants, you can produce just as good plants from seed as you can from. It is certainly a cheaper method.
Sow the seed in early spring. First of all, rake the soil into a fine tilth and then take out a drill 2.5 cm (1”) deep. If you are planting more than one row, make the drills 30 cm (1’) apart. Then sow the seed thinly in the drill and cover it.
The seeds should germinate within 6-12 days. Fairly soon afterwards, when theare large enough to handle, thin them to 30 cm (1’) between each plant. Water the plants frequently in hot weather and keep down by hoeing. In the following spring, treat the bed in the same way as one newly planted with thongs or crowns.
If you are not prepared to wait two years for a crop, then you should grow plants from planting crowns, which can be obtained from nurserymen. Plant the crowns in early spring, using a dibber to make holes about 23 cm (9”) deep. It is normal to space the holes 30 cm (1’) apart with 38 cm (15”) between the rows. However, you should modify this spacing if you are planning to blanch the seakale outdoors using special seakale pots or smallish wooden boxes. In this case you should plant the crowns in triangular clusters of three with 23 cm (9”) between each plant in a cluster and 1 m (yd) between the clusters both in and between the rows.
Whatever spacing you are using, however, rub or cut off all the pointed buds on the top of the crowns before you plant, or they will grow up into unwanted flowering shoots. Then plant the crowns in the holes, cover them with 5 cm (2”) of crumbled soil and pat the soil into a small mound over each plant.
Care and cultivation
Seakale does not require a lot of attention during the summer. Water the plants frequently during hot, dry weather, keeping the soil moist. A mulch of moist peat, garden compost, seaweed or rotted manure in late spring is a good idea to help keep down weeds as well as to retain the moisture. Remove with a hoe any weeds that do grow through and remove all flowering stems as soon as you see them. For extra strong crowns, give a dressing of sulphate of ammonia at 30 g per sq m (1 oz per sq yd) halfway through the summer.