Not only is the leek a well known tasty winter vegetable but its root system has the added advantage of improving heavy soils. Leeks are in the ground for quite a long time and do take a fair amount of hard work but are well worth the effort and it is not surprising that they will be found on every vegetable plot. Sow the seed thinly in a nursery bed in March and April 2cm deep in rows 15cm apart. As soon as possible thin the seedlings to 3-4cm apart. When the young leeks are the thickness of a pencil and about 20cm tall they are ready for transplanting, about 12 weeks after sowing. Water the nursery bed the day before lifting. Make a series of holes 15cm deep in rows 30cm apart with 15cm between holes. Lift the young leeks and trim a little off both the leaves and roots, drop one plant in each hole. Do not fill in the hole but water in each hole. Keep weed free and water reguarly. To increase the length of blanch gradually earth up the plants as they grow, taking care not to allow any earth between the leaves. Earthing up should be complete by October. Winter varieties can be left in the ground as they are very hardy.