Growing Green Onions, Leeks, and Shallots

Growing Green Onions, Leeks, and ShallotsWelcome to the rest of the allium family! Green onions, leeks, and shallots are all popular garden additions and kitchen staples. Depending on your familiarity with these veggies, you may be ready to start growing right away – or you may have some questions. On this page we will give a general overview and, as always, if you think of anything we’ve missed, don’t hesitate to reach out.

Green onions are known by many names, including:

  • scallions,
  • bunching onions,
  • salad onions,
  • and in Canada and the UK, spring onions.

However, be careful, because in some places a “spring onion” is NOT truly a green onion though it does look and taste similar and can be used somewhat interchangeably.

The primary difference is that a true “green onion” is generally either a regular onion plant, that is harvested early or it is a different type of onion that was never meant to form a bulb. These types have long green tops and are known for their milder onion taste, with the most intense flavors concentrating in their white bottom flesh.

On the other hand, true “spring onions” will have a small bulb on the bottom portion which can be used similarly to a pearl onion, and can be red or white depending upon the plant’s variety. They are sweeter than regular onions, but their green ends have a more intense flavor than that of typical green onions. This difference is most apparent when the vegetables are eaten raw. If they are cooked, the flavors become significantly milder. Scallions are the green, stalk portions of either type of these alliums.

While green onions are relatively common, leeks do not typically enjoy the same familiarity. Often known as one of the more costly vegetables in the grocery store, leeks are a favorite among chefs but rarely purchased for the home. This makes their delicate flavor that much more of a treat when you can grow them in your own backyard! With a taste that is similar to that of an onion but much milder yet complex, leeks make an excellent addition to soups and stews and are also delicious on their own, such as right off the grill. In the Middle Ages, leeks were even prepared with honey as an all-natural cold remedy.

Frequently said to have a flavor reminiscent of a cross between common garlic and a sweeter, milder onion, the fragrant shallot rounds out our dive into the allium family. Somewhat resembling its relative, the red onion, shallot bulbs tends to have burgundy, copper or gray skin. However, once you open the shallot, you’ll quickly see it more closely resembles a bulb of garlic with its multiple cloves. Unlike onions, shallots do not grow in rings. A large shallot bulb may contain four to six cloves, while a small bulb will likely contain up to three cloves. When cooking, the way to account for shallots in a recipe is to use one entire bulb (all of the shallot cloves) for each shallot called for in your recipe’s instructions.

Start Growing Green Onions, Leeks, and Shallots

One notable characteristic of these members of the allium family is that gardeners love them because they are such easy crops to grow at home! Known for their ability to thrive whether started from seed, “set” or transplant. Moreover, whether you plant them indoors or outside, alliums are willful germinators that you can expect to thrive for years and years.

When and Where Should You Grow Onions, Leeks and Shallots?

Regardless of which type of allium you are planning to grow, you’ll need to begin with a healthy soil that is ready to become a permanent home to your crops. Alliums are not known to be exceptionally picky as to the specific nutrient condition of their soil, but they do prefer a balanced pH specific to the crop you intend to plant.

  • For green onions, the pH should be between 6.0 and 7.5.
  • For leeks and shallots, we should be aiming for a soil pH between 6.0 and 6.8.

When planning your garden bed, keep in mind that adequate drainage is a top priority. All plants require excellent water drainage in order to prevent root rot and other moisture-related issues.

Additionally, you’ll want to make sure that you select an area of your garden which aligns with the sunlight needs of the crop you are planting. All three of these thrive in full sun. However, shallots are more tolerant of some shade.

Growing Green Onions, Leeks and Shallots From Seeds

Green Onions

Green Onions can easily be grown from seed with a little preparation. Seeds will take one to two weeks for germination. This means that upon reception of the green onion seeds, you will need to sow them in the soil as soon as the ground is able to be worked and all danger of frost has passed. You can start the seeds indoors six to eight weeks prior to planting outside if you choose. Remember, anytime you begin seedlings indoors, they must be acclimated to outside conditions over the period of a week or two prior in order to avoid shock.

Leeks

Leek seeds germinate indoors easily. Simply form a thin layer of moist potting soil to start them. The recommended time to start the seeds is six to eight weeks prior to the last frost. Young leeks must also acclimate to outside conditions. An outdoor enclosure will help ease the acclimation process.

Shallots

Shallots are the most varied species among the alliums discussed within this page, in reference to beginning growing methods. Growing shallots from the bulb is the most common and easiest method to begin with. However, shallots grown from seed are thought by some growers to taste better based upon spending more time in soil.

Starting shallot seedlings requires individual small cells of potting soil. Begin by dropping 2-3 seeds in each cell, then cover with a thin layer of compost or potting soil. We recommend you start shallot seedlings indoors by late winter. Finally, as with all seedlings, before transplanting fragile baby shallot plants outdoors, be sure to acclimate the plants over the course of a week.

Growing Green Onions, Leeks and Shallots From Transplants

The majority of growers agree that most alliums are easiest to begin through transplants, as opposed to seed. Whereas seeds must germinate, transplants only need to be placed into their permanent homes and their living roots will take hold in any quality soil under the proper conditions.

Green Onion Transplants

The next time you purchase green onions, at the grocery store or from a local source, leave approximately two inches of stalk above the root section when you are chopping up the scallion. Aim to include some green portion of the stalk if possible. It is hypothesized that the chlorophyll in this part of the plant acts as food, drastically increasing the transplant’s growth potential over the next few days.

Next, rehydrate this root portion in a glass with an inch or two of water overnight. You want to make sure the glass has just enough water to cover the roots and the white portion of the onion stalk. Place the jar on the windowsill or somewhere where it will receive plenty of light. The next morning you may see new pieces of onion sprouting up already! If you wish, you could choose to keep this green onion plant on your windowsill indoors. After a few weeks, it will have grown enough to begin harvesting.

However, we prefer to prepare our green onion transplant for the outdoor garden, which you can do too. Simply follow these simple steps:

  1. To begin, prepare a medium-sized container suitable for planting. Be sure there are several drainage holes in the bottom of the cup and around the sides.
  2. Fill the cup halfway with seed starting mix and bury your newly rehydrated green onion, root-side down approximately one inch into the soil. Make the hole with either your finger or the handle of a garden tool.
  3. After planting the onion, fill the hole with water like a small bucket. Do not refill the hole with dirt. The hole will fill back in naturally.
  4. Within a few days, you should have a much larger green onion transplant which is ready to be moved outside. In order to do so simply repeat the process, you used to plant it in the cup! After planting, water the entire bed thoroughly.
  5. Make sure to leave approximately eight inches between each of your green onion plants.

If you are planting your green onion from a “set,” be sure to follow the same instructions as for planting an onion transplant. However, you will want to plant the onion “set” slightly shallower and make sure that the root hairs are pointed down.

Warning: While sets often promise faster crop production, they also carry a higher risk of “bolting” or flowering. This is because the “set” being planted is actually an immature bulb in its second year of life. Though these bulbs are kept cool and most will produce adequately, due to the biennial nature of the plant, the risk of bolting remains.

Leek Transplants

When planting leek transplants, they should be spaced 24-36 inches apart. To start, it is simplest to dig a six-inch deep trench for your leeks. Additionally, the soil conditions should be the same as they were for green onions. Just remember that if you will be planting multiple alliums, you need to keep in mind the additional feeding needs of your plants and the nutrient values of your soil.

Once the leeks start to rise up out of the garden, begin “hilling” the ground around their base. Some growers even use the cardboard insert from paper towels to create a type of sheath for the plant as it grows. You need to create darkness around the stalk so that the white flesh can develop undisturbed. The simplest method is just to pile the dirt up around the base of the growing vegetable. Moreover, leeks have large leaves which extend from the base directly opposite one another. For this reason, when placing try to ensure that the leaves are aiming into the adjacent plants.

Shallot Transplants

Shallot bulbs can be planted whole, about 7-9 inches apart, with their root side down. They should be covered almost entirely with soil with only their very top showing above the soil line. Shallots branch off additional bulbs from the bulbs that you plant, so ensure you give them plenty of space. This is key to a fruitful plant.

Watering and Mulching Requirements

Alliums tend to grow readily as long as they receive plenty of moisture. That said, as with all of our vegetables, always make sure your allium bed is draining adequately as excess dampness can lead to problematic conditions. Generally speaking though, the use of a soaker hose or irrigation system and quality organic mulch, will provide alliums with an environment to thrive in with little maintenance.

Like other hearty alliums, leeks need consistent watering. However, take care to avoid over-watering them. If the trenching or tube method of blanching isn’t appealing, a layer of mulch will help maintain a white stalk. When you plant leeks in rich, moist soil, they will grow a large root system.

Shallot transplants can be mulched with a thin layer of straw to protect the soil and roots from the elements. Be sure to not over mulch once the greens poke through the first layer of straw.

Companion Planting and Rotation Considerations

Members of the allium family thrive when planted in close proximity to members of the cabbage family. Chamomile is also known to enhance the flavor by introducing calcium, potassium, and sulphur to the soil.

Leeks tend to require more room to themselves but do interact well with carrots and beets, as the leeks can benefit from the vegetables’ nutrients, while the vegetables appreciate that the leeks deter carrot flies.

One thing alliums do not like is competition. And, beans and peas are lifelong enemies for all three of these plants, so you will definitely want to keep them as far away as possible.

Common Pests and Diseases for Green Onions, Leeks and Shallots

Gophers are a major nuisance pest for members of the allium family. We recommend that, when preparing your bed, you install a layer of gopher wire along the bottom-most layer in order to prevent the animals’ entry to your crops. The gopher-wire is highly recommended over other types of wires such as chicken wire. This is due to its heavier gauge which is galvanized and woven more tightly.

Additionally, because the tops of these vegetables look so tasty from above, quite often birds may become intrigued and decide to investigate our gardens. When this becomes a problem we recommend placing bird netting over your crops. Or have some fun and build a scarecrow or two!

Harvesting and Storing Green Onions, Leeks and Shallots

Green Onions

After 70-90 days, green onions are ready to harvest and eat. The optimal harvest time is when the green onion is young and tender. Another sign for harvest is when the green onion tops reach the width of a pencil. At this time, lightly remove the soil around the plant with your fingers and pull upward on the entire plants. You want to be sure the roots remain whole.

Storing green onions can be done by refrigerating them in an open jar with one inch of water. Cover with a plastic bag and change the water every two days.

Leeks

With a limited storage window, timing the harvest of your leeks can be a little tricky. It takes about 100 to 120 days for leeks to reach peak maturity. They have a large and complex root system. Due to this, it is best to use a garden fork to loosen the roots and pull from the stem once the crop has reached maturity.

Upon picking leeks from the soil, the next step is to peel the first few layers of the stem and trim the excess tops. They will keep for 7 to 10 days in the refrigerator if the stems are wrapped in a moist towel. Overwintering your leeks is also a good option if storage is an issue. They will require another hill of soil and a thick layer of mulch.

Shallots

Like onions, shallots have an easy tell when they are ready for harvest. The bulbs take 90 days to mature. When they do, they have a tendency to let their tops droop and the bulb will begin to protrude out of the soil bed. Once you notice this, loosen the soil bed and pull the bunches out, roots and all. Braid the tops of your crop and hang to dry. If weather permits, hang them to dry near your garden for a week.

Saving Seeds from Green Onions, Leeks and Shallots

Green Onion Seeds

Green onions are biannual. This means that they flower on the second year of planting. This is a great opportunity to harvest the green onions for their seeds. Allow your green onions to blossom until the flower dries out. Cut out the flower and store them in an area that is dark, dry, and cool. The seeds will shake out as the flower fully dries. Dried seeds can be stored in an envelope or paper bag for several years, or until you are ready to plant more green onions.

Leek Seeds

Saving your leek seeds is about as straightforward as it is with the rest of the allium family. The larger leeks will begin to bloom first. Insects will pollinate the flowers, and once the seeds are ready to collect, the blooms will dry out. Cut the flowers and shake out the seeds, or wrap a paper bag with a rubber band around the flowers to collect the seeds.

Shallot Seeds

As with other biennial alliums, the shallots plant have to go through an entire life cycle before they will bloom the following year. Allow the blooms to dry, and shake the seeds into a paper bag. Storage of shallot seeds requires a larger expanse for isolation. You will want to store shallot seeds with 800 feet to half a mile of isolation between varieties.

Choosing the Best Green Onion, Leeks and Shallots Seeds for Your Conditions

Choosing Green Onions

Green onions can be separated into three primary types: short day, long day, and intermediate.

These terms refer to the amount of sunlight the plant requires. Moreover, the easiest way to determine which type of plant is best for you is based upon your distance from the equator.

  • “Long day” onions need 14-16 hours of sunlight in order to bulb
  • “Short day” onions which begin bulbing at around ten hours,
  • “Intermediate day” onions, which require between 12-14 hours of sunlight each day in order to bulb.

The closer to the equator you are located, the “longer” days of sunlight you have available to your garden. The closer to the poles you are located, the more variable your sunlight is.

In the United States, the Northern part of the country can feel most comfortable growing longer day green onions, while the southern parts of the country can feel most comfortable growing short day varieties. Nearly everyone in the United States, other than those located in the Southern-most parts of Florida and Texas, can feel confident growing Intermediate day green onions too.

Choosing Leeks

Leeks varieties have several subdivisions but fall into two main groups:

  • Summer Leeks
  • Fall Leeks

Each name corresponds to the season in which the leek can be picked. With a mild winter, some varieties of leeks can be overwintered.

Choosing Shallots

Shallots come in wide varieties that are grown around the world. They can, however, be split into two major groups, long and short shallots.

  • Long shallots have a narrow bulb with a golden skin. This variety has a tendency to be more hearty for early planting.
  • Short shallots can be identified by their round shape and copper/red skin. This variety of shallot prefers a growing cycle that begins in the spring.

Both varieties tend to yield vast amounts for the season.

Additional Tips for Green Onions, Leeks and Shallots

  • Green onions are high in Vitamin C, and free of fat, cholesterol, and sodium.
  • Never plant an onion set that is larger than a dime, as larger sets are more likely to bolt.
  • Though leeks contain proportionately fewer thiosulfonates than garlic, they still possess measurable amounts of the antioxidants diallyl disulfide, diallyl trisulfide, and allyl propyl disulfide. These compounds convert to allicin by the enzymatic reaction caused when the leek is crushed, cutting, chewed, etc. Allicin has been shown to reduce cholesterol formation and may have antiviral, antibacterial and antifungal properties. Allicin also reduces blood vessel stiffness, improving blood pressure and reducing the risk of coronary artery disease and stroke.
  • Leeks are high in folic acid, niacin, riboflavin, thiamin, pyridoxine, and Vitamins A, C, K and E. Folic acid is critical during pregnancy. The essential vitamins found in leeks are beneficial because they help your body build defenses against infectious disease and harmful free radicals.
  • If shallots are being grown from bulbs, they may be grown in the fall. If growing from seed, it’s important to check the color of your shallot first. Gray shallots thrive when planted in the fall. Red and gold shallots are typically dormant in the fall and should be planted in the spring instead.