Once the leeks main stem has become pencil thick, it’s time to plant out.
Against all your ideas, the best way to do this is to dig a deep hole where their final place will be, prick them out of their pots, cut off half their leaf growth, and snip their roots, leaving about an inch of root. Place the leek so all of its main body is under ground, just showing a few leafy stumps. Now, just fill the hole with water, and leave.
This ensures the leek has plenty of growing space. The cutting of the roots encourages a vigorous root growth, and cutting the leaves and burying of the main body of the plant ensures that the blanching process keeps the stems nice and white.
Basically do everything that feels wrong to the poor leek.
Originally posted 2018-06-07 20:00:45.