Leeks: The Noble Vegetable for All Seasons

Mar 24, 2016

The Napa County Master Gardeners' field testing committee is currently growing two varieties of leeks. One is ‘Lancelot'; the other is ‘Megaton'. I started mine from seed in late January. By planting different varieties, you can harvest leeks practically year round. Early types are ready to harvestfrom early to mid-fall. Mid-season varieties are ready from early to midwinter, and late-season varieties can be harvested in early to mid-spring.


Leeks are a winter-hardy crop with a mild onion flavor. Their edible shank, six to ten inches long, can reach two inches in diameter. For a winter crop, plant seeds directly in the garden in fall. You can also purchase nursery seedlings, which looklike pots of unmown grass. You will need to untangle these seedling clusters and plant them individually.


Plant seedlings as soon as the soil is dry enough to work. Dig a six-inch-deep trench and plant seedlings six inches apart. You can also poke holes with the handle of a rake or hoe and drop the seedlings into the holes. Watering will wash enough soil around them to cover the roots. The holes will fill with soil gradually as the plants grow, keeping the shanks pale. This process is known as blanching, and the more blanching the better.The blanched shank will be tender, while the strappy green leaves can be tough.


Leeks are slow growers, requiring 120 days or more to reach one inch in diameter. They prefer full sun; fertile, well-drained soil; and regular watering. Moisten the soil thoroughly once a week to a depth of 18 inches. Organic mulches help conserve water, supply nutrients and reduce weeding. After the leeks reach sufficient size, you can harvest outer leaves, but beware that harvesting too many may limit the growth of the shank.


Control weeds through regular cultivation, taking care to avoid damaging the shallow leek roots. Weed control is particularly important during the first two months. Onion maggots can destroy leek seedlings and will continue to feed as the bulb expands. To control them, consult the University of California Integrated Pest Management guidelines (http://www.ipm.ucdavis.edu/PMG/r584300211.html). For other common pests and diseases that may affect your leeks, read the university's pest-management tips for onion and garlic (http://www.ipm.ucdavis.edu/PMG/selectnewpest.onion-and-garlic.html).

To prepare leeks for eating, cut away the tough, thick greens. Reserve them for stock or toss them in the compost. Leeks can be frustrating to clean because soil is often lodged between the layers. If you intend to cook the leeks whole, slit them lengthwise, stopping about two inches short of the root end. Trim the root end but leave it intact. Wash well under running water, making sure to rinse between the layers.


If you are going to be slicing or dicing the leeks, first remove tough outer layers and trim away the roots. Slice or dice the leeks, then add them to a bowl of water, swishing well with your hands to dislodge any dirt. Lift the leeks out with a wire-mesh sieve or slotted spoon.

Leeks add a delicate onion flavor to soups and stews. Make a potato-leek soup or braise sliced leeks with peas.

Poach them whole, chill them and serve them with mustard vinaigrette. Or saute them and add to an omelet or frittata.

Leeks store well. Refrigerate in a plastic bag and use within a couple of weeks. They are low in calories and contain kaempferol, a phytochemical that may protect against some cancers.

Legend has it that, in 640 A.D., Welsh warriors led by King Cadwallader placed leeks in their hats during battle to distinguish themselves from Saxon enemies. References to leeks growing in Egypt can be found in the Bible. Ancient Egyptians held the leek in such high regard that swearing by this member of the onion family was the same as swearing by one of the gods.

Workshop: U. C. Master Gardeners of Napa County will lead a workshop on “Growing Tomatoes” on Sunday, April 10, from 2 p.m. to 4 p.m., at the Yountville Community Center, 6516 Washington Street, Yountville. Topics include soil temperature requirements; types of tomatoes; care and fertilizing; support choices; and integrated pest management techniques for common tomato pests. Register at the Parks and Recreation Department at 707-944-8712 or on its web site.

Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. U. C. Master Gardeners of Napa County ( http://ucanr.edu/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site.

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