If you love leeks, then now is the time to make them a part of your garden. What’s great about the leek, which is somewhat related to onions, is that it is a hassle-free and hardy vegetable that you can plant in the early spring or winter.
Leeks are so hardy that hail, storms, and frosts will not bother them. Get to know more about how to grow leeks through this article.
Quick Facts About Leeks
- Botanical name: Allium ampeloprasum
- Common name: Leek
- Family: Amaryllidaceae
- Type of plant: Annual, perennial, vegetable
- Size upon maturity: 1 to 3 feet tall, 6 to 12 inches wide
- Type of soil and pH level: Well-draining soil, loamy; neutral or acidic
- Sun exposure: Full sunlight
- Bloom time: Spring
- Hardiness zones: USDA zones 5 to 9
- Native area: Africa, Europe
Leeks are strongly related to garlic, chives, onions, and shallots that belong to the allium family. If you have plans to plant and grow leeks, then be aware that these plants are capable of producing bundles of narrow, long, and flat blue-green leaves with a base that has a cylindrical white shaft.
Leeks resemble green onions in the way they look, though, the former still has a bigger profile. You will immediately notice its onion-like flavor, though it is sweeter and milder. One thing to note about leeks is that compared to other alliums, these veggies are incapable of forming bulbs.
It is going to be their cylindrical, thick, and long white stalk that you can use in recognizing them. As you grow leeks from seed, keep in mind that they fall under the cool season crop category, but you can let them adapt in a way that they can grow in various temperatures.
Leeks are also known for their rate of growth, which is either slow or moderate. It would also be ideal to plant and grow leeks during the spring, though, there are several cases when you can plant them during the fall.
The good thing about growing and cultivating leeks is that it allows easy access to these vegetables considered as a nutrition powerhouse. Aside from having low-calorie content, leeks are also rich in essential vitamins and minerals, like Vitamins B6 and C, Vitamin K, iron, manganese, and folate.
Similar to other plants that belong to the allium family, you will also realize once you start to grow leeks from seed that they are rich in flavonoid antioxidants. The good thing about these flavonoids is that they carry anti-diabetic, anticancer, and anti-inflammatory properties.
Major Categories of the Plant Leeks
Various leek varieties belong to either of these vegetables’ two major categories – the short-season and the long-season. Here’s how you can differentiate the two:
Also called the early-season leek, you can expect leeks belonging to this category to be ready to harvest in just fifty to one hundred days after you plant the leek seedling. These short-season leeks grow to have milder taste, smaller sizes, and less hardy nature compared to the long-season varieties.
Despite that, they are perfect for gardeners who only have a short growing window during the cool season. Under the short-season leek category are the following varieties:
- Lancelot – This refers to an adaptable hybrid of leek with the ability to grow white shafts, around twelve to fourteen inches, and features dark blue-green flags. Expect Lancelot to grow in several zones with the ability to mature within 75 days.
- King Richard – You can expect this leek variety to mature within 75 days. These leeks grow to have slender and long stems with a tender and sweet taste. You can sow it densely to grow small leeks that you can use in your salads or soups or as garnishes in your recipes.
- Varna – This particular leek variety works well during the early season. It matures within 50 days and starts its growing season by that time. This tall bunching type of leek is usually developed because of its thick direct seeding ability capable of producing clumps or groups of slender plants.
There is also what we call the long-season leek, which usually requires over a hundred days to mature. Some of the varieties under this leek category even require 180 days to mature after you transplant them.
One more thing that makes long-season leeks distinctive is the fact that you can often leave them on the ground after reaching maturity for storage purposes. You can do that for a max of 210 days. It could also be until the freezing of the ground.
Under the long-season category are larger leeks that can tolerate the cold better. You can also store them longer. They can greatly benefit from the blanching process. Here are the most common leek varieties that fall under the long-season category:
- American Flag – This is famous for being one of the heirloom varieties considered the tallest. It features narrow and long shafts and a sweet and mild taste. It works well when it comes to overwintering during mild climates.
- Autumn Giant – This is another heirloom variety of leeks, which is known for being tall, allowing it to reach a height of over thirty inches. Expect this variety to be ready for harvest within 130 days.
There are also those that belong to the third mid-season category, which includes leeks with a maturity period of around 90 to 120 days. Most varieties of leek belong to the mid-season and the long-season categories.
Should You Plant Leeks During the Early Spring?
Yes. The early spring is the perfect season for planting and growing leeks. You can plant these vegetables right around the last spring frost date in your area. One great thing about leeks is that their young plants are capable of withstanding light frost.
Meanwhile, mature leek plants can handle heavy frosts. To start the growing season, begin leek seedlings indoors, specifically around ten to twelve weeks before the anticipated last spring frost date. If you live in a place with climate composed of mild winter, it would be ideal to plant and grow leeks during the fall.
Choosing the Best Planting Location
The most appropriate planting location for your leeks is one that is sunny. Aside from receiving full sun, you also need to make sure that the soil is well-drained and rich. You can also choose to plant them in containers and raised garden beds in case your garden space is not that big.
One thing to remember about leeks is that they have shallow root systems. This makes it necessary to exercise caution in terms of cultivating other plants close to them. Make sure that your chosen planting location is free of weeds, too.
This is necessary for preventing your leeks from having competition when it comes to the nourishment provided by the nutritious soil. If you only have limited space, the best choice is to plant fast-growing and shallow-rooted salad greens between each leek as you wait for this vegetable to get established.
How to Sow Leek Seedlings?
If you plan to start leeks indoors, begin to sow the earliest leek varieties beneath a cover during the late winter. Sowing the leek seedlings involves sieving the potting soil into open flats or pots first then tamping down the potting soil gently.
The seeds should then be sowed around one inch apart in pots or trays. Alternatively, you can sow two seedlings for every cell within a plug tray. Use a thin layer of sieved potting soil to cover the seedlings before watering them.
Make sure to maintain the moisture of the potting soil but prevent it from becoming too wet. Put the seedlings you sowed early in a greenhouse or indoor windowsill that receives sufficient amounts of sunlight.
Once the seedlings become bigger, it would be beneficial to separate them into pots. Support the plant and stimulate the growth and development of its strong roots and solid stature by giving them haircuts using a pair of scissors every week.
What you should do is cut off all except the two-inch bottom of the leek plant. Doing so is a major help in forcing the energy of the plant back to the roots.
The Right Spacing, Support, and Depth
To promote the healthy growth of leeks, it would also be ideal to know the appropriate spacing, support, and depth of the plants. It helps to plant leek seeds at a depth of around one-fourth inch. The spacing should be six to eight inches apart.
As you plant the leek seeds, it is advisable to mound the soil in the area surrounding the stem to the first leaf. Make sure that the rows are also properly spaced, a minimum of one-fourth apart preferably. There is no need for a support structure for leeks.
Start the leek seeds indoors by using the moist soilless potting mix to fill a shallow tray. Cover the leek seedlings lightly using the potting mix since you will need to provide them with some light for proper germination.
You can maximize the results with the help of a heat mat designed to maintain the soil temperature at approximately 70 degrees F. Put your container under grow lights or a bright and sunny window.
Keep the soil moist without making it soggy. Expect the germination to take place successfully after around two weeks.
How to Propagate Leeks?
The good thing about leeks is that you can easily propagate and regrow them from scraps as a means of creating new leek plants. By doing that, you will be able to put the stems of the leeks you do not intend to eat into proper use.
Do the propagation or regrowing of the leek scraps anytime they are growing. The only thing you should do is to take out a healthy leek leaf while ensuring that its roots and stem remain intact.
Cut down the green leaf to around one inch over the roots. Put down the piece roots in a small container or glass of water then place this under a window that receives bright light. One thing you should ensure is that the part where the stem is should not be submerged deeply in water.
The next thing to do would be to refresh the water every two days or so. Expect new growth to appear in around one week. You have the option to harvest the newly planted leeks when necessary or stimulate a more significant and substantial growth by planting seedlings of leeks in the soil.
Growing Leeks in Pots or Containers
You can choose to grow leeks in a pot or container if your garden space is not that big. By doing that, you will be in control of the moisture and light conditions. Pick a pot or container that is around one foot wide.
It also has to be around eighteen inches deep. This option gives you the opportunity to add at least one plant in a container provided each one has a space of around six inches per side.
Avoid making the pot get overcrowded with plants as it may only lead to smaller leaves. Another important thing when it comes to growing leeks in a pot or container is that you have to use one that has sufficient drainage holes. Pick an unglazed clay pot since it lets any excess moisture in the soil evaporate.
Caring for your Leek Plants
Now that you know how to successfully plant and grow leeks, it is time to learn a thing or two when it comes to caring for these vegetables. In this case, your focus should be on these key areas to increase your chances of producing healthy and delicious leeks:
You have to provide leeks with sandy or loamy soil with excellent drainage capabilities. The required pH level is slightly acidic to neutral. Also, keep in mind that well-nourished soil is what your leeks need to grow healthily, so it helps to perform soil amendments using rich compost or organic matter.
Leeks are also fond of sunlight. This makes it necessary to provide them with a minimum of 6-hour direct sun every day. If they don’t receive enough sunlight, there is a risk for them to experience floppy and weak growth.
One key fact about leeks that you have to be aware of is that their root systems are kind of shallow and you need to water them frequently. It is highly likely that leeks thrive in any environment if they receive around one inch of water every week.
A lot of environments for leeks can help make them grow when you provide deep watering every week. The problem occurs if your place often experiences warm or extremely hot weather or climate.
In that case, you have to increase the amount of water you provide your plants. It also helps to mulch. The reason is that mulching can maintain the coolness of the soil, prevent weeds, and preserve moisture.
Humidity and Temperature
What’s good about leeks is that they seem to be capable of growing regardless of the temperature. Despite that, it would still be ideal to plant and cultivate leeks if the temperature is already over 45 degrees F when the spring season comes.
You can also expect leeks to grow well if the temperature is around 55 to 75 degrees F. Humidity is not also a major factor in the healthy growth of leeks, provided you preserve adequate moisture in the soil. Ensure that the plants also have nice airflow around them.
The fact that a lot of gardeners growing leeks harvest these vegetables before they start flowering and seeding, the process called pollination will not create a major issue. If you prefer pollination to take place, though, make sure that you allow your leeks to produce flowers. That way, bees and all the other beneficial insects will help in pollination.
One more fact about leeks is that they do not fall under plants classified as heavy feeders. Note, though, that it may take time for leeks to mature. This makes it necessary to provide them with nutrient-dense soil, one that can assist and support leeks as they grow.
In that case, you can use an organic fertilizer rich in nitrogen or composted manure. Side-dress the soil with it during the middle of summer. You may also want to consult the instructions indicated on the label to determine how much you should use it.
How to Harvest Leeks?
Harvest leeks by digging or twisting and pulling them to take them out from the ground. If you live in an area with a warm climate, expect this plant to continue growing. They will also continue to produce leeks that you can harvest the entire winter.
In areas with cold climates, it is possible to prolong the harvest season, allowing you to dig leeks as long as posibble. The only thing that you have to do is to surround your plant with one thick layer of mulch. Once you have harvested the leaves, wash them thoroughly to get rid of all the soil.
Store harvested leeks in your refrigerator for around one week. You can also blanch and freeze leeks that you have just harvested. These frozen leeks can last for a max of one year.
Pests and Diseases Affecting Leeks
The good thing about leeks is that the number of pests affecting them is still lesser than the majority of garden crops today. With that in mind, it is safe to say that growing them is not that huge of a hassle.
Leeks, together with other allium family members, including onions, also have this natural ability to deter some insects and pests. Despite that, it is still crucial to learn about the pests and plant diseases affecting them so you will know how you can help get rid of them:
These small insects are small and yellow-brown in color. They are among the most annoying problems when it comes to growing leeks as they have the tendency of sucking the leaves of the plants.
You can expect them to be more apparent in places that are dry and hot. Onion thrips focus on growing in tight folds in between each leaf. They usually feed on new growth. Handle this problem using organic techniques.
For instance, you can use a neem oil spray to get rid of onion thrips. It is also ideal to use beneficial insects, like predatory thrips and lacewing larvae, as a means of controlling these insects biologically. One more thing you can do is to remove those plants heavily infested by insects.
They refer to the larvae derived from the harmful onion maggot fly. These pests have sizes that resemble houseflies. They tend to lay eggs close to the base of leeks and other allium plants.
This is where you can expect their larvae to come out and start feeding on roots, bulbs, and seedlings. The result is reduced growth or wilting. There is a high chance for these maggots to appear if the condition where you have planted leeks is cool and damp.
Fortunately, there is a way to control them. What you should do is apply beneficial nematodes or perform organic control.
There are also certain fungal diseases that may affect your leek plants. Among them are white rot, pink rot, purple blotch, allium and leek rust, Botrytis leaf blight, and downy mildew. If a fungal disease affects your leeks, it would be best to use a neem oil spray to prevent them from spreading and causing severe damage to the plants.
You can also use an organic fungicide in the form of a potassium bicarbonate spray. Just make sure to dilute this spray first before use to prevent further damage to your plants.
Allium Leaf Miners
Your leeks may also get infested by the invasive insects that came from Poland, the allium leaf miners. Presently, you can find these insects in Mid-Atlantic and Northeast US regions.
Allium leaf miners are actually pests that resemble the fly. They tend to pierce and feed on the sap of your leek plants. They also tend to lay their eggs inside the tissues of plants. Handle this problem using organic methods and spraying the affected parts with neem oil.
Frequently Asked Questions (FAQs)
Will leeks come back every year?
Yes. The main reason is that leeks can be classified as perennials, making them capable of coming back each year. Also, note that the leeks are capable of producing flowers during the second year and side shoots every year.
What is the best month to plant leeks?
The best time to plant leeks would be during the early spring. They have a texture that lets them tolerate hail, storms, and frost.
Are leeks difficult to grow?
No, it is not difficult to grow leeks at all. It has a straightforward planting and growing process and you can expect it to be ready for harvest soon.
Where do leeks like to grow?
The best place to grow leeks is in a spot where they receive full sun most times of the day. It is also crucial to plant them in well-drained soil that has plenty of organic matter.
Do I have to prune leeks?
In general, there will be no need to prune leeks during its growing season. You just have to harvest its mature leaves. Note, though, that it is still vital to get rid of diseased or dead leaves to ensure that the entire plant does not end up getting weak.