How To Blanch Leeks

Blanch leeks to help them grow whiter stems with improved flavour. If you sowed Leeks in February in South Africa, April is the time that they are ready to start the blanching process. Blanching is the term used when you push soil up against the stems so that the vegetable develops white stems. You do this in stages and will improve the flavour, making it milder.

Leeks Growing in Garden Beds

To blanch leeks grown in a normal garden bed, simply push up the soil around the stems by about 5cm each time.

Start by placing a collar around the leeks to prevent the soil from getting in. Place it around the leek up to the base of the leaves.

A collar can be a piece of plastic piping or strong brown paper secured with string or rubber bands.

The collar must not strangle the plant. Place another collar above the first one as the plants grow and are earthed up.

Leeks Growing in a trench

To blanch leeks growing in a trench, gradually fill the trench with soil to the bottom of the lowest leaves.

Be careful not to earth up too high or get soil trapped in the leaves. Repeat this until the leeks have finished growing.

Use dry, fine soil to fill in. With wet soil there is the danger the leeks could rot. If the soil is lumpy or clumpy, break it down to a fine tilth, otherwise it may not keep out the light (and it might be difficult to work).

The final blanched stem should be 10 – 15cm long.