Leeks grow slowly and take up space in the ground almost all year, so make sure you have room. Around 20 mature leeks should fit in a square metre.
Sow in April in seed trays – be patient, as leek seeds germinate slowly. Pot on when large enough and then keep them in a semi-shaded spot until they are at least 15cm tall. Alternatively sow three or four seeds per cell in a modular tray.
Caption: Sow leeks in April
Plant individual leeks using a dibber to make a hole around 15cm deep. Drop in the plant, making sure the top is sticking out, and then fill the hole with water. Planting deeply with a trowel works just as well.
Caption: Planting individual leeks with a trowel
If you sowed several seeds per cell in a modular tray, plant out the whole clump of plants using a trowel. You don't need to plant them deeply. There'll be less white stem but they'll still be very tasty.
Allow around 30cm between rows to make weeding easier, and space plants at 15cm intervals for full-sized leeks. If you’re short of space, plant closer together and harvest alternate plants as baby leeks, leaving the rest to grow on to maturity.
CARING FOR YOUR PLANTS
Leeks need little attention during the growing season. Keep the plot weed-free and well-watered in dry spells. Cover with insect-proof netting to avoid allium leaf miner and leek moth.
Caption: Grow leeks under fine mesh to keep out pests
Pull leeks as you need them. Ease a fork into the soil next to the leek and gently prise from the ground if you've grown them as individual plants. If you've grown them as clumps, use a trowel to cut out as many leeks as you want from the clump.
Caption: Harvest leeks as and when you need them
■ Rust Leek rust is a fungal disease that causes rusty-orange blotches on the leaves. It’s prevalent in warm, moist weather. Severe infections can make the leeks inedible, but this is rare and slight infections will affect only the outer leaves, which can be peeled off, and will usually disappear when the temperature drops in winter.
There aren’t any chemical controls, so your best defence is to dispose of any affected leaves, ensure your plants aren’t crowded to improve airflow and grow your leeks (or garlic) in a different spot each year.
Caption: Leek rust
■ Bolting This is when leeks start to produce flower spikes before the leeks are ready to harvest. It’s usually caused by the weather, with a late, cold spring often to blame. Very hot conditions can also cause bolting. Improving the soil so that it doesn’t dry out may help. Lift any affected plants and use what you can straight away.
■ Leek moth and allium leaf miner The caterpillars of leek moth cause pale-brown patches on the leaves as they feed. Destroy any caterpillars or pupae you find. Undamaged parts of the leeks can still be used. Allium leaf miners tunnel through the leaves and stems in spring and autumn and you may find their brown, barrel-shaped pupae if you peel back the leaves in autumn and winter. To avoid both pests, use a tunnel made of very fine netting, such as Best Buy Enviromesh, which will stop the adult insects
laying their eggs on the plants.