Leeks (Allium ampeloprasum, var. porrum, syn. A. porrum)
This member of the Allium family is thought to have been in cultivation since the 2nd century BC, from ancient Egypt to Mesopotamia. The Romans believed that eating leeks imparted a sonorous voice — to the point that the emperor Nero had leek soup served to him every day in an effort to increase the volume and resonance of his orations. He was nicknamed the porrophage (porrum being the Latin for leek) by his senators, essentially “leek-mouth.” From what we know about leeks in the historical record, it’s possible they were cultivated in early Mesopotamia.
Leeks have held close association with Wales for centuries, often worn alongside the daffodil as a symbol of national pride. In Shakespeare’s Henry V, Henry tells Fluellin that he wears a leek, “…for I am Welsh, you know.” The Welsh dish cawl is a traditional soup dating from the 14th century that combines leeks, root vegetables, and meat. In any event, leeks are particularly well suited to gradual harvest, as they stand in the field well, and many varieties are cold hardy. It is no surprise that they were cultivated right across the north of Europe. It is a famous theme ingredient of Leek and Potato Soup.
The edible portion of the leek is the stem, composed of a series of overlapping leaf sheaths. Cut in cross section, these segments fall apart into a series of rings. The goal for leek growers is to “blanch” the largest and longest portion of the stem by covering it with earth, either in trenches, or by hilling soil up around the stems as they grow. This prevents sunlight from contacting the blanched stem, which remains white and tender, and slightly sweet, while the dark green leaves of the plant become tough, chewy, and bitter. The tops of leeks are much better suited for making vegetable stock than for serving raw or cooked.
Summer leeks are sown indoors very early and transplanted in early summer for harvesting late summer to early fall. Winter leeks have been bred for greater cold hardiness, and are left in the ground over winter for harvests the following spring. The term “pot leek” comes from the UK, where each year plant breeders compete to grow the largest leeks. These are traditionally blanched by planting them inside clay drain pipes, and can reach sizes of 6” in diameter, although at that size they tend to be rather tough.
Wild leeks (A. tricoccum) are known as ramps, and grow wild in the woodlands of eastern North America. From Appalachia to Ontario, annual ramp festivals are a spring tradition. Ramps have a much more pungent flavour than leeks, often compared to a combination of onions and strong garlic. On the first Saturday in May each year, the town of Bradford, Pennsylvania celebrates “Stinkfest,” where ramps are served in a variety of cuisine styles to music from local bands before the annual Outhouse Race down Main Street.
How to Grow Leeks:
Difficulty: Easy. Leeks are not well suited to container growing.
Timing: Start summer harvest varieties in February/March in flats indoors. Start fall harvest and overwintering varieties from March to May in a humus-rich nursery bed outside and then transplant.
Sowing: Sow seeds 1cm (½”) deep, thin to 1cm (½”) apart. Transplant when 20cm (8”) tall. Seeds germinate in 8-16 days, depending on soil temperature. Space 10-15cm (4-6”) apart, in rows 45cm (18”) apart.
Soil: Fertile soil with lots of compost and ¼ – ½ cup complete organic fertilizer worked in beneath each 2m (6’) of row. Aim for a neutral pH in full sun.
Growing: Use a dibber to make holes 15cm (6”) deep. Set a transplant at the bottom of each hole and cover with soil up to the first leaf notch. Leave the rest of the hole unfilled—rain will fill it in as the leek grows. To blanch further, hill the soil up around the stem as the leek grows, or mulch with straw.
Harvest: Dig any time the leeks are 2cm (1”) in diameter or larger.
Storage: Overwintering leeks are so hardy they are best stored in the ground. Otherwise, they will keep in a root cellar for several weeks. One of the best storage methods is to make a giant batch of leek & potato soup, and freeze individual portions.
Seed info: In optimum conditions at least 75% of seeds will germinate. Soil temperature for germination: 10-25°C (50-75°F). Usual seed life: 1 year.
Growing for seed: Individual varieties should be grown in isolation of 1km (½ mile) from one another — but only if growing for seed.
Pests & Disease: Like most other Alliums, leeks are relatively trouble free. Practice diligent crop rotation.
