Calabreses in Cambridge

Sow seeds indoors in modules or small pots from 26th February - 13th March. Use a good seed compost and cover lightly with 1 cm. Keep at 15–20 °C for germination, which takes 7-10 days. Water gently to keep the compost moist but not soggy.

Once seedlings have two true leaves, prick them out into individual pots from 19th March - 26th March. Handle by the leaves to avoid stem damage and plant at the same depth. Use a potting compost and water well after transplanting to settle the roots.

Gradually acclimatise plants to outdoor conditions over 7-10 days from 9th April - 16th April. Start by placing them outside in a sheltered spot during the day, bringing them in at night. Increase exposure each day to prevent shock when transplanting.

Transplant hardened-off plants to their final growing position from 26th April - 10th May. Space them 45 cm apart in rows 60 cm apart. Firm the soil well around the roots with your heel to prevent wind-rock, a technique known as the 'Brassica Stomp'. Water in thoroughly.

Protect plants from pests immediately after transplanting from 3rd May - 10th May. Cover with fine mesh netting to keep out cabbage white butterflies and pigeons. Fit brassica collars around the base of each stem to deter cabbage root fly larvae.

Apply a nitrogen-rich fertiliser every 28 days from 28th October to support leafy growth. Use a balanced liquid feed or granular fertiliser, watering it in well. Stop feeding once the main head starts to form to avoid over-fertilisation.

Harvest the central head when it's firm and tight, cutting it with a sharp knife about 10 cm down the stem from 28th October. Leave the plant in the ground to produce side shoots, which you can pick regularly until 2nd July. Water consistently to prevent bolting in dry weather.