Tip Top Leeks

Large vegetables can sometimes be associated with a certain lack of flavour, but ‘Shirleys' Giant Exhibition’ leeks combine the best of both worlds, as Paul Peacock explains

The Allium family – onions, garlic, chives and so on – has proven to be very useful to mankind, having excellent medicinal as well as culinary uses. These are among the very earliest cultivated plants, and have been in continual use for over 8,000 years. Their distinctive flavour is due to sulphur-rich chemicals that form the plant’s immune systems, and when we eat them they benefit ours too.

These chemicals have been copied in the past to create antibiotics, and are in use today in the fight against the sort of super-bugs that plague some hospitals. In fact, it may well be this property that led to the old adage: ‘eat a leek a day you’ll last forever’. Who knows?

But what is certain is that leeks are the most pleasing of plants to grow and, in many parts of the North East and Wales, they’re still grown (in the face of stiff competition) for money. All kinds of equipment and ‘secret methods’ are used to produce the perfect specimens for showing; they are planted in split drainpipes using special compost, drip-fed with nutrientbearing water, and often turned a little each day to keep them growing straight.

‘Shirleys' Giant Exhibition’ will attain a really good girth if you want to use it in a show. It also has generally perfect conformation, and the way the leaves splay out from the firm white flesh looks almost like a set of tiles on a Chinese rooftop. But by far and away the best reason for growing them is their flavour!

Soil Conditions

Leeks are easier to grow than onions because they are tolerant of a wide range of soil conditions. They prefer a rich soil that isn’t loose in texture, and is reasonably well draining. But you can grow them on clay or sand as well. The only thing that really worries them is water-logging.

Sow the seeds in containers indoors during April or May, or even in a seedbed outside – it really doesn’t matter which. By the time midsummer arrives, in late June, they will be as thick as a pencil, and ready for transplanting into their final growing positions. Alternatively, you can buy ready-started plants (see our offer from Victoriana).

Once transplanted into their final positions, leeks will happily stay in the ground right through the winter, resisting both storms and frost. As long as the soil around them is firm they’ll be fine, and they should be harvested when you need them. This can be at any time after they’ve reached a size where you can’t get your thumb and forefinger around them.

Transplanting

People new to growing leeks might worry about this, but it’s really easy and the plants respond well to what appears to be harsh treatment!

Flatten the plot (I use a plank that I walk over) and use a dibber – or even a bulb planter – to create holes that are 15cm deep and about 24cm apart. Ideally, the row should be spaced at 40cm intervals. Take the young leeks and cut off all but the last 4cm of root, and trim the top of the leaves by the same amount. You now have what looks like a bunch of prepared salad onions.

Drop one plant into each hole, then fill the hole with water. It doesn’t matter if the water washes a little soil over the roots, all you need to make sure of is that the plants are upright. From this position they will happily grow to maturity.

Blanching

Some people increase the length of the whiteness in the stem by blanching the plants. Blanching cuts out the light to the growing stem and instead of growing green photosynthesising tissue, they remain white. Earthing them up, like potatoes, has always been the traditional method of doing this. Simply use a hoe to draw soil up around the stem. If you don’t want the leaves to get dirty then, instead of earthing-up, you can achieve the same effect by fitting collars made from of sawn-off drainpipe.

Feeding

These plants do especially well if they are planted in an area where a previous crop has received a heavy load of manure, or following a crop that adds nitrogen to the soil, such as beans. Potash deficiency can lead to increased fungal infection, so a spray with organic fertiliser at the transplanting stage can help. Apart from this, though, leeks require very little care, save the odd watering when the weather is really warm and dry.

Pests & Diseases

• Rust: This takes the form of an orange deposit on the leaves, and can ruin the plant. It can be treated with an organic copper-based fungicide. Although it’s unsightly, it can be eaten or, if you prefer, simply cut away. However, plants that are really badly affected should be burned.
• Onion fly and leek moth: In both cases, eggs laid on young leeks hatch to give grubs that tunnel through the plant tissue. Infested plants should be burned. To counter these two you can cover young plants with fleece until they are well established.
• White rot: This is another fungal infection that’s promoted by the sort of humid conditions that occur in overcrowded beds. So, to avoid it, leave plenty of space in between the plants to ensure that they stay dry.You can recognise this one by the tiny cotton wool-like strands produced. It also leads to rotten bulbs and, usually, inedible plants.

This article first appeared in the June 2007 edition of Grow It! magazine. To download a pdf copy of the original article click on the image below...