Calabrese – Brassica olearacea var. Italica Rotation group – brassicas
More commonly known as green sprouting broccoli it is mostly grown as a summer vegetable. Unlike the looser spring sprouting broccoli Calabrese forms a tight green head during the mid- late summer.
Varieties to choose (sold by Kings Seeds):-
Sow
Calabrese is grown from seed it but doesn’t like being transplanted. To keep any root disturbance to a minimum it is best to sow two or three seeds in modules filled with fresh seed compost during February – March. After the seed has germinated remove all bar the strongest seedling using a scissors, don’t be tempted to pull the unwanted seedlings out because it will disturb the roots of the selected seedling. When the roots of the single plant are showing near the sides of the modules it is time to pot them on in to 3ins/9cms pots. When they have produced four true leaves they will be ready for planting out into the open ground. Transplant them 18ins/45cms apart in the row with 18ins/45cms between the rows. Water them regularly until they start to produce new leaves.
A second sowing can be made during April-May to produce a follow on crop in the early autumn.
Growing on
Water the plants regularly throughout the summer and feed weekly with liquid seaweed. The earliest transplants will need to be protected against frost so keep a cloche or fleece nearby. Draw soil up around the stalk of the growing plants to just under the first set of leaves.
Aftercare
Protect the young leafy plants from pigeons and keep a look out for cabbage white butterflies laying their eggs on the undersides of the leaves. Squash the early broods but you will have to spray with insecticidal soap or Bacillus thuringiensis to control the caterpillars. Hoe regularly between the plants to keep the soil weed free. Never let the plants dry out.
The earliest sown plants can be ready to harvest from late June onwards and the later sowings will be ready throughout August and September. Cut off the entire central head and leave the plants in the soil to produce a follow on cluster of smaller florets.
Cabbage root fly is the main danger it attacks soon after transplanting; the female lays her eggs close to the plants and as the young white maggots develop they eat their way along the roots causing the plants to collapse by day and seeming to recover in the cool of the evening. It is best to dig up any plants that show these symptoms and destroy them. A 6ins/15cm mat made from damp proof coursing may help as it forces the eggs to be laid too far away from the root system for the maggots to survive.
Large and small cabbage white butterflies lay their eggs on the undersides of the leaves and the caterpillars can quickly reduce the leaves to stalks. Small mesh netting suspended over the plants will give some protection but it does make working in between the plants difficult. Spraying the leaves with the biological pest control Bacillus thuringiensis will kill the young caterpillars without harming anything else. It is available from biological pest control suppliers.
Club root which is the curse off any member of the brassica family and is impossible to control it flourishes is poorly drained acidic soil. That is why it is best to raise your own pot grown plants using John Innes soil based compost and definitely not a peat type.