I like to sow leeks thinly in a cold frame in mid- March. For early crops you sow seeds in a tray in the greenhouse in late February and prick out into a cold-frame when 10cms high, ready for planting out in early May. You can see in the photo young leek seedlings growing on in late March
By late April the young plants of early sowings, having reached a length of about 20cms, are ready for transplanting into a well-prepared bed, manured for a previous crop. I make a hole with a dibber a good 15cms deep and drop a plant into each hole., spacing plants in blocks 20cms x 20cms apart. I then water the hole and keep the bed well watered thereafter until the young plants are well established. Later sowings are ready for planting out in May and early June.
By late May early crops are starting to race ahead. I always keep a few plants back to fill in any gaps. If you have weedy ground it is well worth growing plants through black polythene or cardboard. This method also helps to conserve moisture as leeks like plenty of water. My favourite leeks are all heritage varieties including an early maincrop Gigante D’Inverno and Blue Green Autumn which are both very hardy and can stand through the coldest of winters.