Giant Dinverno

A huge Italian Variety, Leeks are best grown in modules before being transplanted to their final growing position later. They are very easy to grow from seed. Sow one or two seeds per module just 1cm deep.
They will take about two weeks to germinate. For a continuous supply of leeks sow as follows:
February – plant out in April, will be ready to eat in early autumn
March – plant out in May, will be ready to eat in early winter
May – plant out in June, will be ready to eat in late winter
Leeks are heavy feeders so it’s best to grow them in fertile soil that has been enriched with plenty of farmyard manure or compost. Spread a general purpose organic fertiliser before planting out. They will be ready to plant out about 2 months after sowing (when they are pencil thick). The process of planting leeks is called “puddling in” and feels a little counter-intuitive but works very successfully. Here’s how it works: Make a 6-inch hole with a dibber, drop the leek in and then fill the hole gently with water. Do not backfill with soil – over the coming weeks it will fill itself (see, I told you it would feel counter-intuitive!). Leave 15cm between plants and 30cm between rows. Keep the leek bed well weeded..
Leeks have to be earthed up during the growing season – this process encourages the bleaching or whitening of the stem. If you don’t earth up you will be left with leeks which are predominantly green with just a small amount of edible white stem. Earth up twice during the season.
The best leeks are the small tender ones – they decrease in flavour as they grow larger, so don’t aim to produce prize-winning ones. Lift the leek with a fork – their roots are surprisingly fibrous and strong. Winter varieties can stay in the ground until needed, they are practically indestructible.