Leeks

Source: [1]

Years grown at UBC Farm/LFSOG: two/zero

Growing conditions

Light, moist, nutrient-rich soils are best for growing leeks. This crop is frost tolerant but grows slowly. Thus, early varieties must be sown indoors; late varieties can be sown outside directly.

To sow seeds indoors, start by placing seeds one and half cm deep, about four per cm in rows 7cm apart on a five cm deep tray. Sprout at about 20C and grow at about 18C during the day (14 hour days) and about 10C at night. Do not thin but do trim their tops to maintain a height of about 7cm. transplant outdoors when stems are about half a cm in diameter or by May 1st. outside, seedlings are placed into a 15-20 cm deep and wide trench. The bottom of this trench should consist of well loosened, fertilized soil. Space seedlings 5 cm apart and cover with soil up to the first leaf joint. As the leeks grow soil should be added to keep the soil just below this leaf joint, this maximizes the edible portion of the leek. Sowing seeds outside requires careful soil preparation; it should be mixed with compost and fertilized with a complete organic fertilizer resulting in potting soil-like conditions about 8 cm deep. Create one and half cm deep furrows, 30 cm apart, and sow about 3 seeds per cm, cover with loose soil. Aim for one seedling per cm, thin if necessary. Once seedlings are about one cm in diameter (mid summer) they are transferred to trenches as described above.

Keeping the soil moisture around 70% at all times is generally all that is needed to keep leeks growing well as they are quite hardy and generally do not have problems with pests or disease (Solomon, 2000).

Seasonality

There are two main types of leeks: fall, which are harvested in the fall, and winter, which are harvested in the winter and spring. Fall leeks require a very early start; they are sown indoors under lights in mid February and then transplanted outside by May 1st. These will be ready for harvest during September and October when the stems are about three cm or larger in diameter. Winter leeks are sown outside in early May and then transplanted around mid July to trenches for their final growth phase. These can be harvested from November to May (Solomon, 2000).

Nutritional Information

Leeks like other alliums, including garlic and onion, have long been recognized for their health promoting properties. Most health research regarding alliums has focussed specifically on the effects of onions and garlic consumption, which have been shown to be anticancer, antiasthmatic, antibiotic, and beneficial to cardiovascular health. It is thought that leeks offer similar benefits. Dedicated research on leeks has revealed anticancer effects and antiplatelet activity (Rabinowitch & Currah, 2002).

Leeks along with other alliums may pose a health risk to people with serious kidney or gall bladder problems. This is because they contain naturally occurring oxalates, which can crystallize in the body if they become too concentrated.

When selecting leeks, look for those that are firm and straight with white lowers and dark green upper leaves, avoid any with yellowing, cracks, or bruising. For the best texture, i.e. not too fibrous, choose leeks that are under four cm in diameter.

Fresh leeks should be stored loosely in plastic unwashed and untrimmed in the fridge for up to two weeks. Alternatively, leeks can be blanched and stored in the freezer for up to three months. Cooked leeks spoil quickly; expect spoilage within two days in the fridge.

Before eating leeks some trimming and cleaning is normally required, begin by cutting off the root tip and upper leaves where they become dark green. Next, remove the outer layer and make a length-wise cut center-deep, spread open while passing the leek under running water to flush out any soil trapped in leaf folds (The World's Healthiest Foods, 2010).

Nutrition Facts/Valeur Nutritive
Serving Size: 250mL (raw)
Amount Per Serving	%Daily Value*
Calories 32
Total Fat 0g	0%
Saturated Fat 0g	0%
Trans Fat 0g
Cholesterol 0mg	0%
Sodium 19mg	1%
Total Carbohydrate 13g	4%
Dietary Fiber 2.5g	10%
Sugars 4g
Protein 1g
Vitamine A	0%
Vitamine C	20%
Calcium	5%
Iron	14%
* % Daily value based on a 2000 calorie diet

Note: Nutritional information derived from data provided by Health Canada.

Recipes

Braised Salmon with Leeks

[2]

This recipe is a powerhouse for supplying two difficult to find health-promoting nutrients for your Healthiest Way of Eating — vitamin D and omega-3 fatty acids. One serving provides 123% of the daily value (DV) for vitamin D and 106% DV for omega-3s. And it only takes 15 minutes to prepare. Enjoy!

Prep and Cook Time: 20 minutes Ingredients:

2 medium leeks, cut lengthwise

4 medium cloves garlic, pressed

1 TBS + 1/2 cup chicken or vegetable broth

1 TBS + 1 TBS fresh lemon juice

1 TBS fresh chopped tarragon

1-1/2 lbs salmon fillet, cut into 8 pieces, skin and bones removed salt and white pepper to taste

Directions:

Cut off green tops of leeks and remove outer tough leaves. Cut off root and cut leeks in half lengthwise. Fan out the leeks and rinse well under running water, leaving them intact. Cut leeks into 2-inch lengths. Now, holding the leek sections cut side up, cut lengthwise so that you end up with thin strips, known as chiffonade cut. Make sure slices are cut very thin. Let leeks and garlic sit for at least 5 minutes to bring out their hidden health benefits. Heat 1 TBS broth in 10-12 inch stainless steel skillet. Healthy Sauté leeks over medium heat in broth for about 5 minutes, stirring frequently. Add garlic and sauté for another minute. Add ½ cup broth and lemon juice and simmer for another 5 minutes, covered, stirring occasionally. Rub salmon with 1 TBS fresh lemon juice, salt and white pepper. Stir fresh tarragon, salt, and pepper into leeks, and place salmon on top of leeks. Simmer for about 3-4 minutes, covered, or until salmon is pink inside. Time may vary a little depending on thickness of salmon. Serve leeks topped with salmon and drizzle with juice. Serves 4 Serving Suggestions: Serve with Pureed Sweet Peas

Healthy Cooking Tips:

It is best to choose salmon that is cut from the thickest part of the fish, so filets will remain more moist when cooked. If you want to remove the bones from the salmon rub your fingers over the salmon to find the line of bones. Remove each bone with your fingers, tweezers, or pliers.

Refer to the animation for cutting the leeks: Leeks Cut Lengthwise. When they are cut into thin strips they provide a nice bed for your salmon with more texture than simply slicing them crosswise. It is important to cut the strips thin, as they will not get tender without cooking them for longer. Even thought this recipe is for 4, I cut the salmon into 8 pieces. They cook more evenly when cut small. Otherwise the outside of the salmon gets overdone before the center is cooked. Check the salmon's doneness by inserting the tip of a knife into the center. It should flake, yet be still pink in the center for medium. Remove it from the heat slightly before it is done to your liking, as it will continue to cook while you are serving the dish (The World's Healthiest Foods, 2010).

Steamed Leeks

A super simple side dish to compliment any meal.

Prep and Cook Time: 10 minutes

Ingredients:

4 Medium leeks

Directions:

Chop leeks into rounds about two cm thick and steam. Season with butter and salt and pepper

Serves 4

Additional usage inventory

Leek leaves are used to tie up herb bundles known as “bouquet garni” which are then used to make soup stock in traditional French cuisine (wikipedia, 2010).

Leeks are worn to celebrate St. David's Day, the Welsh national holiday, every year on March 1st. They are also worn at international rugby games held in Wales since they are one of that country’s national emblems (Historic-uk, 2010).

Academic connections

None apart from its educational value as a crop that can be observed growing throughout the year.

References

Historic-uk. (2010). The Leek - the national emblem of the Welsh. Retrieved from

       http://www.historic-uk.com/HistoryUK/Wales-History/TheLeek.htm

Rabinowitch, H.D. & Currah, L. (2002). Allium crop science: Recent Advances. New York: Wallingford, Oxon

Solomon, S. (2000). Growing vegetables west of the Cascades : the complete guide to natural gardening. Seattle, WA: Sasquatch Books

Wikipedia (2010). Bouquet garni. Retrieved 2010-03-22 from
        http://en.wikipedia.org/wiki/Bouquet_garni

The World's Healthiest Foods. (2010). Leeks. Retrieved from http://whfoods.org/genpage.php?tname=foodspice&dbid=9

Additional notes

Leeks are scientifically known as Allium ampeloprasum porrum, this genus has over 700 species, including onion and garlic. Leeks were first cultivated by the ancient Egyptians about 4000 years ago and subsequently spread to medieval Europe. Today leeks are still a popular crop in Europe and are gaining popularity in the USA and beyond (Rabinowitch & Currah, 2002).

Lessons from the UBC Farm:

Difficulty of Growing: 4 (on a scale of 1 to 5, where 1 is the easiest and 5 is the most difficult)

Very slow growing, requires diligent weeding, watering and fertilizing (Tim Carter, UBC Farm Production Coordinator, personal communication, March 16, 2010).