By Dr. Mercola
If you’ve never tried leeks, you may be interested to include them in your fall garden this year. Actually, you can grow leeks year-round, but given their hardiness to cold, they make a great fall crop. If you live in an area with mild winters, you can even leave leeks in the ground during winter and harvest them in early spring. Now is the time to consider growing (and eating more) leeks.
Taking a Peek at Leeks, the Tall, Leafy Cousin of Garlic and Onions
Leeks (Allium ampeloprasum porrum) are a member of the allium family vegetables, closely related to garlic, onions, scallions and shallots. Given their thick green sheaths and long floppy leaves, leeks stand out in the crowd. In fact, leeks grow 12 to 30 inches tall, 9 to 12 inches wide and 1 to 2 inches in diameter.1
Often considered to be a root vegetable, leeks don’t typically form a bulb. When it’s been blanched and kept tender, you’ll find the bottom 6 inches of a leek’s leaf sheath to be the most edible and enjoyable part of the plant. When preparing leeks for eating, you can compost the tough upper leaves or use them to make stock. Due to their cold hardiness, you can plant leeks year-round. As such, they were featured in my article titled Plan and Plant Your Fall Garden Now.
Leeks are biennial and will grow a flower stalk in the second year. That said, you’ll want to harvest them in the first year. Only allow leeks to bloom if you are interested in saving seed; otherwise, treat them as an annual.
Though they were once rarely seen outside of potato-leek soup in the American food mainstream, leeks are growing in popularity. They have a long history of culinary use around the world, including northern Europe. Thought to originate in the Mediterranean and Central Asia, leeks also were cultivated by the ancient Egyptians and Greeks and popularized by the Romans.2
The subtle, mild flavor of leeks adds depth to a variety of dishes, including salads, soups, stews and stir-fries. Leeks can be enjoyed cooked or uncooked. They add antioxidants, beneficial fiber, bulk and as well as important vitamins and minerals to any meal.
Suggested Leek Varieties You May Want to Try
Mother Earth News suggests types of leeks you may want to try, based on your choice of growing season, as follows:3
- Summer leeks: Lincoln, Kalima, King Richard, Rikor or Titan
- Fall and early winter varieties: Falltime, Imperial, Tadorna or Varna
- Winter-hardy types: American Flag, Blue Solaise, Giant Musselburgh, Siegfried or Winter Giant
In most U.S. regions, says Mother Earth News,4 the winter-hardy varieties will endure winter and resume growing in early spring when temperatures warm. If you plant winter-hardy leeks, be sure to mulch them well and harvest them in the spring before they flower and produce seed. If you wait to harvest them until late spring, chances are they will have turned woody. As such, to ensure the best flavor, harvest winter leeks between January and April.
How to Grow Leeks
When planning for leeks, be sure to plant them early in the growing season because most varieties take 120 to 150 days to mature. If you want them ready sooner, seek out one of the modern cultivars that have been bred to be ready in about 90 days. Below are tips from gardening experts on how to grow leeks:5,6
Leeks do well either direct-sown or as transplants. If you live in a cold climate, start seeds indoors, using a loose, well-aerated seed-starter mix, eight to 12 weeks before your last spring frost. Give them plenty of light. When outdoor temperatures remain above 40 degrees F, you can harden the plants off slowly during a period of seven to 14 days and then transplant them in your garden.
In warmer climates, you can start seeds indoors three to four weeks prior to your last spring frost and then transplant your seedlings outdoors for an early summer harvest. Another option is to direct-sow seeds in your garden in late summer for a winter through early spring harvest.
To avoid damage from diseases and pests known to linger in the soil, choose a planting site where onions, garlic and other alliums have not grown for several years. Check out the featured video above for two demonstrations on the best way to plant leeks in your garden.
Although they will tolerate somewhat alkaline soil, leeks thrive in slightly acidic soil with a pH of 6.0 to 6.8. To fuel the growth of their long leaves, you’ll want a loose, rich soil with lots of organic matter. If desired, you can add a balanced fertilizer during the transplanting process.
Because leek leaves grow in the same direction, you can set your transplants out as close as 2 to 6 inches apart as long as you allow room for the leaves room to branch out into the spaces between rows.
Leeks thrive in full sun.
Pests and problems
In terms of pests, watch out for onion maggots, thrips and slugs, which may nibble leaves and stunt growth. Leaf rot or leek rust can be a problem in the case of damp weather, wet soil or poor air circulation, so be sure to let the soil dry out between waterings. Remove any infected plant material as soon as it appears.
Provide about 1 inch of water weekly. If desired, you can mulch the plants to help retain water, cool the soil and prevent weeds. By the way, weed control is vital to the success of your leeks because they don’t like to compete with weeds for water and nutrients.
Although leeks are not heavy feeders, due to their long maturity, you may want to apply a side dressing of composted manure or a high-nitrogen fertilizer midseason. Alternately, you can apply fish emulsion fertilizer occasionally throughout the growing season to keep your leeks growing strong.
Two Tips to Ensure Your Success When Growing Leeks
Below are two tips provided by The Spruce to ensure your success when growing leeks:7
• Blanching: Leek shafts are made tastier through a process called blanching, which blocks photosynthesis, thereby keeping the plants tender and sweet. You can blanch your leeks by planting them in a trench or mounding up soil or straw at the base of the plants as they grow. Another option is to place wide boards alongside your rows in the shape of an inverted “V” when your leeks reach a height of 8 inches. All of these methods block the sun’s access to the plant, thereby creating a white sheath.
• Grittiness: Due to the tight formation of their sheaths and close proximity to the soil, leeks are well-known for attracting grit. As the plant grows, soil can easily become trapped between the leaves. One way to keep them cleaner is to slip a cardboard tube, such as those used for paper towels and toilet paper, over young leek plants. Not only will the tube keep out the grit, but it will also disintegrate naturally.
Because leeks don’t die back like onions, signaling their readiness, it’s best to wait to harvest them until the base feels firm and solid and is at least 1 inch in diameter.8 The best way to harvest mature leeks is to dig them up with a gardening fork. When harvesting immature leeks, simply twist and pull them from the soil.
As mentioned, leeks are frost tolerant. If you live in a mild climate you can leave them in the ground all winter long. Because leeks will store better in the ground than in your refrigerator, harvest them in small batches and use them within a day or two.
Tasty Ways to Prepare and Enjoy Leeks
When preparing leeks for eating, the hardest part may be removing the mud and grit they’ve attracted while in the ground. Due to the blanching process, which may have involved trenching, your leeks might contain layer upon layer of dirt. An effective way to clean leeks is to start by cutting them in half lengthwise and rinsing them well. Another option is to soak them in cold water for several minutes and then rinse them afterward.
Taking extra time to wash your leeks well is important says Dani Lind, owner and operator of Rooted Spoon Culinary in Viroqua, Wisconsin. She states, “Really take care when cleaning leeks — there’s nothing worse than biting into a mouth full of grit in an otherwise carefully prepared dish.”9 Lind offers the following tasty suggestions for preparing and enjoying leeks:10
Add chopped leeks to soups; consider combining leeks with chicken, cream and potatoes
Blanch chopped leeks in boiling water for a couple of minutes to soften and then add them to salads
Cut leeks in half lengthwise and braise in water with aromatic herbs
Cut leeks lengthwise into quarters, blanch, brush with coconut oil and grill
Poach chopped leeks in an oven-safe casserole dish with wild-caught fish, lemon, white wine and dill
Sauté chopped leeks in coconut oil along with garlic, onions and your favorite herbs
Nutrition Facts for Leeks
Leeks are a good source of vitamins A, B, C and K, as well as calcium, iron, magnesium, phosphorus and potassium. Due to the presence of folate, adequate intake of leeks during pregnancy may help prevent neural tube defects in newborns. In addition, the B vitamins in leeks may support heart health by keeping your levels of homocysteine in balance, which is important because elevated levels of homocysteine are associated with heart disease, blood clots and stroke.
|Calories from Fat||3|
|Total Fat||0 g||0%|
|Saturated Fat||0 g||0 g|
|Total Carbohydrates||14 g||5%|
|Dietary Fiber||2 g||7%|
*Percent Daily Values are based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.
Eating Leeks May Help Protect You from Cancer and Heart Disease
Leeks are versatile, tasty and easy to prepare. If you are unfamiliar with them, I encourage you to give them a try. As with most vegetables, you may enjoy them more if you grow them in your own garden. Leeks have much to offer in the way of nutrition. Similar to garlic, the therapeutic effects of leeks centers around its sulfur-containing compounds like allicin.
Allicin is a well-known antibacterial, antifungal, antimicrobial and antioxidant agent. When digested, allicin produces sulfenic acid, a compound known for its fast action to neutralize free radicals. Leeks also contain kaempferol, a natural flavonoid found in broccoli, cabbage and kale.
Kaempferol has been shown to help your body resist cancer and other chronic diseases. As reported in Mini Reviews in Medicinal Chemistry:12
“Some epidemiological studies have found a positive association between the consumption of foods containing kaempferol and a reduced risk of developing several disorders such as cancer and cardiovascular diseases.
Numerous preclinical studies have shown that kaempferol and some glycosides of kaempferol have a wide range of pharmacological activities, including antioxidant, anti-inflammatory, antimicrobial, anticancer, cardioprotective, neuroprotective, antidiabetic, antiosteoporotic, estrogenic/antiestrogenic, anxiolytic, analgesic and antiallergic activities.”
Kaempferol is also known to protect your blood vessel linings from damage, possibly by increasing production of nitric oxide, which helps your blood vessels to dilate and relax.13 In a meta-analysis of 19 studies involving 543,220 subjects, researchers found consuming large amounts of allium vegetables, including leeks, may significantly reduce your risk of gastric cancer.14 Another study suggests the consumption of allium vegetables like leeks can protect against other types of cancer too:15
“Allium vegetables have been shown to have beneficial effects against several diseases, including cancer. Garlic, onions, leeks and chives have been reported to protect against stomach and colorectal cancers …
The protective effect appears to be related to the presence of organosulfur compounds and mainly allyl derivatives, which inhibit carcinogenesis in the forestomach, esophagus, colon, mammary gland and lung of experimental animals.”
Fall is a great time to plant leeks. Given their many health benefits and culinary versatility, you’re sure to enjoy growing leeks. If you’re looking for one last reason to plant leeks, check out my Delectable Potato Leek Frittata With Dill and Creamy Mustard Dipping Sauce Recipe. Now is the time to add some leeks to your life!