Growing leek from seed to harvest is fairly straightforward.
Key leek facts
Name – Allium porrum
Family – Alliaceae
Type – vegetable
Height – 15 to 24 inches (40 to 60 cm)
Exposure – full sun
Soil – light, drained
Lead time: sow 5-7 months before harvest – Harvest: summer, fall, winter
Here is our advice on how to grow leek well, from sowing to harvest – without forgetting the all-important ridging!
- Treatment: allium leaf-mining fly
- Health: leek health benefits
Sowing and planting leek
The sowing season for leek extends more or less from mid-January to mid-September.
Sowing can start relatively early in the season, as long as there is a protected space that is relatively warm (above 60°F, or 15°C) like a greenhouse or an indoor space fitted with heating.
- No need to give each seed an individual nursery pot: at an early stage, sowing in a tray is the most effective way to start.
It is of no use to sow leek in the ground directly until soil temperatures reach at least 54°F (12°C).
1- To harvest leek in spring
To harvest leek in the spring, you must have sown the leek at the end of summer or during fall of the preceding year.
- Sow directly in the ground in August or September.
- Thin regularly to give the more vigorous stems the space they need to develop.
- If you prepared your seedlings in nursery pots, transplant in October or November at the latest.
2- For a summer leek harvest
To harvest leek early in the season, it is necessary to sow seeds during the winter.
- Sow seeds indoors in January if you live in mild climates, and in February or March elsewhere.
- Thin as soon as seeds sprout, and again repeatedly as often as needed to ensure that the leek always have space to grow.
- As you thin, you’ll have a steady stream of small but very tasty leek from the beginning of the summer.
3- To have leek to harvest in fall
This is the ideal season to grow leek because temperatures allow for normal, outdoor cultivation.
- Sow the seeds in a nursery or indoors from March to May.
- Thin as soon as seeds sprout, and again repeatedly, as often as needed to ensure that the leek always have space to grow.
- When the stems of the plants have reached ¼th inch (½ cm) across, transplant them to their growing bed, lightly snipping the tips of their roots and leaves to spur regrowth.
- Space them 4 to 6 inches (10 to 15 cm) apart.
- When transplanting leek to the growing bed, space each plant 4 to 6 inches (10 to 15 cm) apart, and space rows 10 to 12 inches (25 to 30 cm) apart.
Caring for leek
Growing leek is very easy, and here is how to ensure a bountiful harvest and avoid diseases.
In order to whiten the base of the leek, it is important to ridge leek stems regularly. This is also called blanching. This is an important step in growing leek because only the underground portion will become the white part of the stem.
- Ridging leek means to gather soil up along the base of the stem in order to create a small mound.
- Only the underground portion stays white, so the more they are buried, the longer this portion will be.
Leek plants only need water in case of prolonged dry spells or heat waves. It’s better to avoid over-watering.
- A normal rainfall pattern should perfectly answer the water needs of leek.
- Water only in case of prolonged dry spells or heat waves.
- Nonetheless, feel free to mulch around leek stems to retain rainfall as long as possible.
- Hay, flax or hemp mulch is perfect.
>> Video tutorial on growing leek <<
Diseases and parasites that attack leek
Leek is vulnerable to certain diseases, and preventive treatment is recommended; but best is to space the stems well to avoid fungus altogether.
Run the hoe along the ground to remove weeds and let rainwater seep into the ground easily.
- Blight: yellow and then brown stains appear on leaves
- Powdery mildew: a white velvet-like layer develops on leaves
- Aphids: leaves curl up and shrivel
- Leek leaf-mining fly: there are efficient treatments sold in stores, but it is possible to use fermented stinging nettle tea sprayed regularly as a preventive treatment against the allium leaf-mining fly
Leek companion plants and incompatible plants
Leek responds more or less well to the presence of other vegetables in the patch. Here are the good companion plants followed by the ones leek is incompatible with.
Leek COMPANION vegetables
In the vegetable patch, it is important to match plants correctly to ensure that companion plants are located near each other.
egetables to grow near leek:
Carrot, celery, strawberry, onion, tomato, lettuce, corn salad or asparagus
Plants INCOMPATIBLE with leek
Certain plants would compete with leek and it is best to plant them apart to avoid them hindering each other.
Bean, silverbeet, cabbage or pea.
Cooking is a very different story altogether, and combining these vegetables together can be very savory.
Vegetables to plant after harvesting leek
For good crop rotation, in order to maintain good levels of nutrients in the soil, here are the vegetables that are suited to planting after leek:
Carrot, cucumber, coriander, squash, bean, turnip, radish or tomato.
Species and varieties of leek
All leek varieties share the same health benefits and therapeutic values.
Some varieties of leek are very interesting:
- ‘Bleu de Solaise’ – hardy, sown February to May, harvested in winter.
- ‘Gros long d’été’ – rather sensitive to cold weather, it is to be sown in spring or summer for a harvest in summer.
- ‘Carentan leek’ – very good, it is to be sown from February to May and harvested from summer to winter.
- ‘Elephant leek’ – the thickest of all leek, it is to be sown as early as February and harvested in the summer or fall.
You will perhaps find solace in the following varieties as well:
- Common leek or ‘Très long d’hiver de Paris’ – perfect as a winter leek.
- ‘Maxim’ – harvested from summer to fall.
- ‘Carlton F1’ – since it grows quickly, it can be sown directly in the open field.
Most leek varieties are very hardy and will let you harvest this vegetable all winter long, straight from garden to table.
- ‘Long de Mézières’ and ‘Bleu de Solaize’ leek also resist cold very well.
Keeping leek seeds
Let a few of the nicest, most vigorous stalks go to seed. Beautiful flowers will pop up that are white or shades of violet. These dry out with tiny seeds in each capsule at the end.
Label a paper pouch with the date and the variety, and store in a cool, dry place that’s well ventilated.
Note that because of cross-pollination, the variety might not come out true, but unless it’s a hybrid, it will keep many of the mother plant’s characteristics.
Tip: those dry flowers make for excellent dried flower bouquets because they hold for a long time.
Learn more about leek
Its origin stems from the Mediterranean sea, and leek is cultivated today almost all over the world.
Very much savored for its taste and nutritional value, leek is also well recognized for its many health benefits and therapeutic values.
It is replete with vitamins C, E, fibers and pro-vitamin A, and leek helps the digestive tracts function correctly and keeps many illnesses at bay.
Leek is a low-caloric vegetable often recommended for diets, which also helps regulate gastrointestinal functions.
Leek can be eaten both raw and cooked, but most leek-based recipes involve cooking it.
- Did you know that green leek leaves often are included in bouquet-garni, the bundle of herbs used to prepare meals for fine dining?
Read also about leek:
Smart tip about leek
Since it has a high fiber content, leek is excellent to ease digestion and also delivers many needed vitamins!
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