How to Plant, Grow, and Care For Leeks in Your Garden
Leeks are related to onions, garlic and shallots. They have a variety of different uses, and are an excellent plant for beginning gardeners and experienced gardeners alike. In this article, organic gardening expert Logan Hailey walks through the best ways to plant, grow, and care for leeks in your garden.
While onions, garlic, and chives get all the attention, leeks are one of the most underrated allium vegetables. These sweet, delicately onion-flavored stalks have a creamy buttery texture when braised. They are nutrient-dense and full of cancer-fighting antioxidants and fiber.
This perennial veggie looks somewhat like an oversized cylindrical green onion stalk with wild tops, leeks are their own species with unique benefits in the garden and kitchen. Due to its long growing season, many gardeners miss out on this exquisite unique vegetable out of fear of losing space in the garden or having to care for a crop for nearly 5 months. But this frost-tolerant allium is redeemed by its small space requirements and low-maintenance needs.
Leeks are essentially an onion’s sophisticated, yet humble cousin. They add an aromatic depth of flavor to sautés, soups, stews, roasts, and more. They also shine in winter cooking when you’ve exhausted your cured onion and garlic stores and are craving something fresh. Best of all, you can start leeks in early spring and harvest them at any size, all the way until mid-winter in most climates. Let’s dig into how to grow the best leeks you’ve ever tasted!
Plant Type Biennial grown as annual
Plant Family Alliaceae or Liliaceae
Plant Genus Allium
Plant Species Allium porrum
Hardiness Zone USDA Zones 2-10
Planting Season Early Spring
Plant Maintenance Low
Plant Height Up to 2’
Fertility Needs High
Suitable for Containers Yes
Plant Spacing 6” plants and 12-24” rows
Temperature 55-75°F is ideal
Soil Type Fertile, well-drained, pH 6.0-7.0
Watering Needs Moderate
Sun Exposure Full sun to partial shade
Days to Maturity 80-120 days
Pests Leek Moth
Diseases White Rot, Pink Root
History and Cultivation
Most of us only know of leeks in the context of potato-leek soup. But this ancient vegetable has roots all the way back to ancient Egyptians, Greeks, and Romans. While the pungent strong-flavored onion is most common in American cuisine, many cultures considered leeks to be more refined and elegant than its intense allium cousins.
What are Leeks?
Leeks (Allium porrum) are robust herbaceous biennials belonging to the Alliaceae (previously part of Amaryllidaceae) family. Members of this family also include onions, garlic, chives, and scallions. Unlike its cousins, leeks do not form bulbs or produce cloves. Instead, they have many layers of leaves that grow around a cylindrical stalk.
Traditionally, the thick base is mulched or hilled to yield the crisp, white neck that is most coveted by chefs. The long elegant leek tops fade from light green to a darker bluish emerald color at the tip. Though some people commonly discard the tops, I find them very delicious when thoroughly cooked. By this standard, the entire leek plant is edible, but gardeners and farmers usually try to maximize the quality of the blanched lower portion.
Leeks have commonly been prepared with potatoes, but their complex flavor is far more expansive with opportunities. They make a surprising, delicious roasted or grilled side dish. Their mild flavor yields well to raw thinly sliced garnishes on spring salads. In the fall and winter, their buttery sweet texture adds a wholesome, rich aroma to soup, pasta, or risotto.
Where Do Leeks Originate?
Leeks likely originated in the eastern Mediterranean region from their wild leek relatives. The vegetable was very popular amongst ancient cultures and quickly spread throughout Europe thanks to its hardy cold-tolerance and versatility.
Historians have found dried specimens at ancient archeological sites in Egypt. The Egyptians even loved leeks so much that they painted tombs and carved walls with images of them. Roman emperor Nero was a renowned leek-lover who believed eating copious amounts of leeks would improve his singing voice.
The delicious Allium porrum was even featured in the world’s oldest cookbook, written in 3rd century Rome. Back then, leeks were often served straight-up like a side of asparagus or broccoli. They were found growing prolifically in Roman gardens and beyond.
Leek Legends and Folklore
At some point, immigrants (perhaps the Phoenicians) brought leeks to northern Europe. The Welsh and Irish in particular came to love this allium and have created all sorts of cultural traditions around it.
For instance, the leek is the national emblem and national vegetable of Wales. It is stamped on the Welsh pound coin and was used medicinally by Welsh ancestors. It is a very important ingredient in the traditional Welsh diet, especially during lent. Common recipes include potato leek soup, leek and cheese tarts, and the national Welsh Dish, which is a thick meaty soup called “Wales is Cawl”.
There are even legends that leeks saved the country of Wales during a historic battle with the Saxons in 640 AD. Saint David instructed troops to put leeks in their caps so the Welsh wouldn’t accidentally mistake their comrades for enemies. On St. David’s Day, Welshmen wear a daffodil or a leek stem on their shirts in memory of the victory over the Saxon invaders.
In Ireland, leeks were also used in many recipes like the Irish potato leek soup, Irish stew pie, and the traditional Boxty potato dish. An old Irish legend says that Saint Patrick was once trying to console a dying woman and she said she had a vision of an herb floating through the air. She told St. Patrick that she had to eat it or she would die instantly. The saint asked her what kind of herb she had envisioned and she responded “leeks”. So the Irish adopted the leek as their own favorite vegetable as well.
Symbolically in both cultures, leeks seem to represent bravery, loyalty, protection, and keeping away evil spirits. It also has an important reputation for its medicinal uses of curing the common cold and helping ease childbirth. Needless to say, there’s a reason this humble green-and-white stalk is so revered in European cultures. Leeks always have a place in their gardens!
Health Benefits of Leeks
Like all allium vegetables, leeks are known to have immune-boosting organosulfur compounds that help prevent illness and protect against inflammation. They are a good source of fiber and prebiotics that feed your gut microbiota and promote better digestion. Some studies even show that people who consume leeks, garlic, or onions on a regular basis may have 49% lower risk of gastric cancer and 79% lower risk of colorectal cancer.
If that isn’t enough, leeks also have lots of Vitamin A, C, and K to promote healthy eyes, skin, and teeth. At the same time, they’re low in calories and rich in antioxidants. Their polyphenols and high amounts of manganese make this aromatic allium even more attractive for your health.
Easy to grow, harvest, and cook, you really can’t go wrong with leeks.
Leeks are usually grown from seeds and may be difficult to find in mainstream garden stores, however many nurseries and organic farms may offer the transplants in the spring. Propagating leeks is very simple, but timing is very important for a successful harvest.
How to Direct Seed Leeks
While transplanting is the most common, you can also seed leeks directly in the garden in early spring. Make a shallow furrow and plant leek seeds ¼” to ½” deep at a rate of about 6 seeds per foot in rows 12-24” apart. Keep thoroughly moist and cover with row cover to protect them. Once the seedlings germinate, thin to 6” apart.
How to Propagate Leeks
Leeks are long-season crops that are usually one of the first things to seed indoors in the spring. This is especially important if you live in a cold short-season climate because the leeks need to be firmly established by the time fall frosts roll around.
The best time to seed leeks indoors is around February, or 12 weeks before the last frost. Sow seeds in flats or plug trays full of high quality-organic potting mix. The little black seeds can be sown ¼” deep and 1” apart. Gently sprinkle soil on top and keep thoroughly moist but not soggy until germination. Place flats in a sunny windowsill, greenhouse, or under grow lights.
Unlike many other veggie crops, leeks are totally fine with having their roots separated and handled. When the leeks reach a 2-4” tall, you can optionally dig them and transplant into individual plug trays. Or, you can allow them to continue developing roots in the open flat.
It is important to give your leek seedlings a “haircut” every few weeks to encourage fat stocky bases. Trim the upper part of the plant, leaving behind about 2-3”. You can use the trimmings like chives in the kitchen. This will funnel the plant’s energy into the roots. By the time transplanting comes around, your baby leeks should be about as thick as a pencil.
Planting leeks is very similar to planting onions, except you can bury them much deeper. In fact, leaving just 1-2” of leaves above the soil surface will encourage lovely stout leeks with white-blanched bases. Leeks are very forgiving and you can’t really go wrong during planting as long as you handle them with care.
If you plan on companion planting with leeks, you have several options. Tomatoes, and beets both do quite well with leeks. They can also flourish with strawberries. Carrots can also make a good pairing, and leeks can keep away the dreaded “carrot flies” that seem to plague many gardeners depending on your growing zone. Kale is also one of the better cold-hardy companions for leeks.
How to Transplant Leeks
By late spring, your leek seedlings should be about 8” tall and pencil-thick. You can prepare your garden beds with a generous addition of compost, rake the soil flat, and then create a 6” deep furrow with the top handle of a garden tool.
Alternatively, you can use a trowel or hori hori to create dibbled holes about 6” deep. The rows should be 12-24” apart and the leeks will be planted 6” apart.
Be sure that your soil is loose enough to go this far down and permit plenty of water drainage. You may need to broadfork the bed to loosen lower soil layers.
Gently slip your hand beneath the soil of the seedling flat or shimmy each plug out of its cell tray. Leeks are resilient to root disturbance and can be gently untangled from each other at this point. I prefer to take all the untangled baby leeks and soak their roots in a small bucket with a gallon of water and 2 tbsp. of diluted fish emulsion. This will make them easier to plant and give them an instant boost once they’re in the ground.
Once plants are separated and soaking, lay them in the furrow or hole with just 1-2” of leaves peeking above the soil surface. This will ensure thick, long, blanched shanks once mature.
Gently backfill with soil, but do not firm it down. Allow your irrigation or rain to help fill the hole so there is plenty of aeration in the root zone. Leeks need consistent water in the first few months of growth.
How to Grow Leeks
Compared to their garlic cousins, leeks are extremely easygoing. With enough fertility and water, they kind of just hang out in the garden all season long, growing slowly but steadily into fat delicious stalks. The only maintenance they require is a little bit of “hilling up” to ensure you get as much of those coveted white shanks as possible.
Leeks require full sunlight and a minimum of 6-8 hours of bright light every day. That being said, they will tolerate some morning or afternoon shade. If growing leeks in an area with partial shade, expect smaller leeks or slower growth.
Leeks have fairly shallow root systems and need plenty of water during establishment. Once rooted, the plants need only about an inch of water per week. Irrigation is essential in areas with dry summers because inconsistent watering can produce extra tough stems and a stronger intense flavor. Thankfully, a thick mulch combined with the hilling process will retain moisture to reduce the need for irrigation.
These large upright stalks require fertile, well-drained soil for the best success. The ideal pH is between 6.0 and 7.0. A generous addition of compost to planting beds will help improve the organic matter levels and improve drainage simultaneously.
Thanks to their compact growth habit, the leeks are also great for containers and small raised bed gardens. Choose a standard organic potting mix with plenty of drainage to keep leeks happy in a container.
Climate and Temperature
Leeks are a cool-season crop that is best planted in early spring and harvested in late fall. They prefer temperatures between 55° and 75°F. Hot weather slows the growth. Young seedlings can handle light frosts whereas established leeks are cold tolerant down to about 20°F. Extra hardy overwintered varieties can go down to 10°F. If they are mulched, they can handle even colder.
Certain varieties (described below) are more heat tolerant and bred specifically for southern climates. As long as they have plenty of water, they can still yield excellent flavor and texture.
Allium porrum are heavy feeders that really thrive on high fertility. This shouldn’t be a problem if you add plenty of compost or organic matter to your garden. Soaking in diluted fish emulsion at planting, and then feeding the plants every 3-4 weeks is a great way to promote more tall, sturdy growth. You can also feed an all-purpose organic granular fertilizer at the time of planting to provide slow-release nutrition throughout the lifecycle.
Like potatoes, leeks require hilling to keep their lower stalks under the soil surface. This will blanch up the shank as far as possible. In a small garden, you can use your hands to mound up soil along the base of the plants or go along the side of the bed with a hoe to mound soil up the stalks.
You should periodically hill the leeks at least 2-3 times during the growth cycle, mounding the soil progressively higher as they grow. Higher mounding yields deeper, longer blanched stalks. If using the “dibble” planting method described above, mounding may not be necessary.
When leeks have reached your desired size (usually around 1” across and 1’ or taller), simply loosen with a spading fork or broadfork and lift the plants. Use a machete or garden knife to cut off the roots. You can cut off the extra ends of the tops, leaving the paler green portions intact. They can be stored in a crisper drawer of a refrigerator or in a ventilated bag for several months, or harvested as needed.
You can also harvest leeks at baby and medium size to use more like scallions in the kitchen.
There are dozens of leeks with a wide diversity of traits. Some are bred specifically for early season plantings (typically more heat-tolerant, quick-growing types) whereas others are bred for winter harvests (the most frost hardy types). I’ve found that most leeks have similar flavors, but the texture and amount of blanching can vary widely by cultivar, water stress, and growing conditions.
Best Cold Hardy Leeks
- ‘Tadorna’: A vigorous open-pollinated leek bred for fall plantings. This variety takes 100 days to mature and produces medium-length bright white shanks with a nice contrast to the dark greenish-blue upper leaves. You can hold ‘Tadorna’ in the garden for winter harvests in moderate climates.
- ‘Bandit’: One of the most winter hardy leeks, this open-pollinated variety has beautiful erect leaves that are deep green and tinted with blue. The stalks grow extra thick without bulbing, requiring 120 days to reach full size (about 2” across).
- ‘Surfer’: A super beautiful deep verdant green-leaved variety with rust tolerance and an easy-to-strip preparation. It stores well and performs best in fall. 110 days to maturity.
- ‘Blue Solaize’: A popular French heirloom, the leaves are truly blue-infused and even violet colored after cold flashes. The leeks grow very long (up to 20”) and large, have a sweet flavor, and are extremely hardy for overwintering.
Best Short-Season Varieties
- ‘King Richard’: One of the best early leeks, ‘King Richard’ can yield leeks with white shanks nearly a foot long! The medium-green leaves are nice and tender. This variety is not hardy enough to overwinter, but will withstand mid-to-heavy frosts. Only 75 days to mature.
- ‘Rally’: An upright, vigorous variety with rust tolerance and beautiful uniform stalks. Takes only 85 days to mature and tolerates a range of weather conditions.
- ‘Hannibal’: Just 75 days to mature these thick pure white stalks with dark green leaves. ‘Hannibal’ is the perfect early season leek with moderate frost tolerance.
Best Heat-Tolerant Leeks
- ‘Comanche’: This refined leek has a long, slender shank and is perfect for midseason growth. It has a more upright habit that makes it easier to weed. 105 days to mature.
- ‘Kilma’: This fast-growing leek takes just 90 days to harvest and is best adapted to hotter summer conditions with less frost tolerance. It yields long 10-12” shanks with gorgeous white to pale green coloration.
- ‘Dawn Giant’: Some of the most giant leeks available! With plenty of water they can resist the summer heat. Fast growing and vigorous, only 98 days to mature.
Pests and Diseases
Due to their milder aroma than their onion and garlic cousins, leeks are sometimes subject to pest issues. They can also fall victim to many common allium diseases. The easiest way to prevent any of these issues is by maintaining a healthy soil biology, providing consistent water (preferably through drip irrigation or soaker hoses), and practicing crop rotation.
If you see bright to neon orange spots on your leek leaves, this is a sure sign of the fungal disease called Leek Rust. It can also be found on onions, garlic, and chives in summer through autumn. The infection can be worse in high-nitrogen soils, so avoid overfertilizing your leeks. It is also important to properly thin between plants to encourage air flow. Some varieties are moderately resistant to rust.
Another common allium disease that also affects garlic and onions, the fungus that causes white rot (Sclerotinia cepivorum) can live in the soil for up to 20 years inside protected propagative balls called sclerotia.
This is the most problematic allium disease around the world that leads to yellowing and stunting, and eventually death of all leaves with a fluffy white fungus growing at the base of the bulb. Practice regular crop rotation, source reliable disease-free seeds, and ensure proper drainage in your soil.
The pathogen Phoma terrestris may initially cause symptoms similar to nutrient deficiencies because it prevents the plant from taking up nutrients. Pinkish to dark purple roots begin to look transparent and water-soaked. Eventually plants will become stunted and die.This fungal disease can get pretty severe if alliums are planted in the same place year after year. Resistant varieties and crop rotation are the best preventative options.
I personally have never heard of a big problem with leek moths, but it is good to be aware of this pest that can feed on allium crop foliage. They stunt plant growth and may impact the storage capacity of the leeks. It is mostly concentrated around New York, other parts of New England, and into Ontario, Canada. Row cover is the easiest means of prevention. A diluted neem solution may also act as an effective repellent.
The most popular portion of the leek is the blanched white shank, however the entire plant is edible. If left in the ground, leeks will even produce a delicious scape similar to those from hardneck garlic. The darker green parts of the leaves can be cooked slightly longer for a better texture or incorporated into broths.
Leeks can be enjoyed raw, roasted, sauteed, boiled, and even pickled. They store well into the winter when held in the garden and harvested as needed. In the fridge, leeks can be stored for up to 2 weeks in a crisper drawer.
Frequently Asked Questions
How long does it take to grow leeks?
Leeks are a long-season crop that average 85 to 120 days to maturity and are best planted in the cool weather of spring and harvested in the fall.
What month do you plant leeks?
Midseason and late season leeks need to be planted as early as possible in the spring. Seeding indoors about 12 weeks before your last frost date (January through March in most climates) is recommended.
Do leeks grow back every year?
Though they are most commonly grown as annuals, leeks are technically a biennial or hardy perennial. They can overwinter and regrow the following year, spreading into a little “colony” of bulbous lateral growths that can be harvested from continuously.
Do leeks like sun or shade?
Leeks prefer full direct sunlight, but tolerate partial shade. It’s best to provide leeks with 6-8 hours of light per day throughout their lifecycle.
Can you grow leeks in a container?
Leeks don’t take up much space and will easily grow in containers and are best planted in a deeper planter so that you can add soil as it grows to blanch the stalks. This mimics the “hilling” method used in the garden.
Can you eat the leaves of leeks?
All parts of the leek plant are edible. Leek leaves have a sweet, mild flavor just like the white part of the shank. Their texture can be a little tougher, so they are best sliced thin or sautéed. The dark green portions of leek tops are often used in broths and stock as well.
There is no need to shy away from crops with long maturity windows once you realize how hands-off they are during the main growing season. If you plant leeks in the spring and passively provide them with proper water and hilling, you will reap the rewards with a tasty aromatic allium flavor in your autumn and winter meals.
There has to be a reason the Greeks, Romans, Welsh, and Irish held leeks in such high esteem! They are low-maintenance in the garden, don’t take up much space, tolerate super cold winters, and can be enjoyed in a wide variety of recipes.