When to plant Calabrese in Durham

Sow seeds indoors in modules or small pots from 26th March - 10th April. 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 9th April - 1st May. 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 30th April - 22nd May. 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 24th May - 7th June. 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 24th May - 14th June. 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.

• Keep the insect mesh clear of the leaves at all times. Cabbage white butterflies will lay eggs through the fabric if it touches the foliage.

Apply a high-nitrogen liquid feed every 28 days from 7th June to encourage strong leafy growth. Water the feed in well. Reduce feeding once the main head starts to form to avoid over-fertilising.

Harvest the central head when it's firm and tight, cutting it with a sharp knife about 10 cm down the stem from 23rd July. Leave the plant in the ground to produce side shoots, which you can pick regularly until 5th October. Water consistently during dry spells to keep heads developing nicely and reduce the risk of bolting.