Cabbages will grow in all kinds of soils, though the varieties that are ready for use in spring prefer a lighter soil, which warms up quickly after the turn of the year and encourages the roots to grow earlier.
Cabbage is a heavy feeder, so spread plenty of manure in the bed at the rate of a bucketful to the sq. yd. make sure that the soil is not acid; apply carbonate of lime at 5 oz. (150g) to the sq. yd. unless the soil is chalky. The optimum pH is 6 to 6.5, greater than 7 the disease clubroot can take hold.
Because they are a hungry crop, taking up a lot of nitrogen and potassium, it should be given frequent top-dressing of nitrate of soda, sulphate of ammonia or dried blood at the rate of ½ oz. (15g) per plant. Cabbage has shallow roots, so cultivation should be shallow. To ensure that the roots are kept cool and moist a thick mulch is an excellent way of doing this and it will help to keep down weeds.
A semi-shady seedbed is best that has been treaded after raking, then raked once more; scratch out drills ½ in. (12mm) deep and 6 in. (15cm) apart. Fertility for cabbages is relatively high so the seed should be sown thinly and a rake used to cover them up; the top should then be firmed with a rake head.
Plants grown as transplants may be planted out into beds that have been well watered the day before. With a dibber make rows of holes in the planting-out area 1½ ft. (45cm) apart, leaving 1 ft. (30cm) between the holes in each row. General Care Hoe between the rows to keep down the weeds. For those types grown over winter, should the soil be heavy, make a 4 in (101mm) furrow between the rows to take away excess moisture.
Poor environmental conditions during growth can lead to problems when the cabbage is harvested. High temperatures and low moisture can cause small plants and give low yield; they also lead to long stems and outer leaves to drop. Cabbage requires about 1 in. (25mm) of water per week, which should be given throughout the growing season to prevent the heads from splitting.
It is a good idea to place a barrier around the plants; this can be a fine net or horticultural fleece, supported by strong, thick, wire stalks in a kind of cloche that will prevent flying insects from laying their eggs on the plants.