Lettuce... continuously

I'm a lettuce addict. There's nothing for me like biting into the melting heart of a Boston, crunching the fleshy leaves of a romaine lettuce, or filling a sandwich with the red, curly leaves of leaf lettuce. Over the centuries, the species Lactuca sativa evolved from its native ancestor Lactuca serriola, which has been present since time immemorial in Asia, the Mediterranean basin, and Ethiopia. Leaf lettuce, Lactuca sativa var. crispa, was first cultivated, notably by the Assyrians, Egyptians, and then the Greeks. Romaine lettuce, Lactuca sativa var. longifolia , was discovered on the Greek island of Kos by the Romans, who brought it to the capital of the empire, where it was cultivated, selected, and improved into the form we know today. Head lettuce, Lactuca sativa var. capitata , the butter type—later named Boston in America—appeared in Europe in the 16th century. Louis XIV was known to have been fond of it and insisted that it be grown in the gardens of Versailles. It was in America that the ice-cold head lettuce called Iceberg was developed, still the most popular on the continent. I particularly love the red leaf lettuce Merlot , the heads Divina and Merveille des Quatre-Saisons, and theromaine lettuce Oreille du Diable .

Although lettuce can be propagated by direct seeding, I much prefer sowing indoors. This prevents the loss of young seedlings to the mandibles of voracious cutworms or earwigs. The technique also allows plants to be established at optimal density while allowing the creation of vibrant scenes with shimmering colors and textures.

Tight control

For indoor sowing, sow a number of seeds slightly larger than the desired number of lettuces. For example, you could sow 8 seeds of leaf lettuce, red Boston, green Boston and romaine, which should produce about 20 lettuces to transplant 6 weeks later. Sow in a row in a tray filled with germination soil composed of 20% well-ripened compost, 40% perlite and 40% coconut fiber, without forgetting to write the name of the cultivars on a wooden stick. The seed should be covered with a few millimeters of soil. Germination is rather rapid. It is important, as soon as they emerge, to place the young seedlings under fluorescent lighting, 16 hours per day.

After 15 days, the first true leaves—those following the cotyledons—unfold. This is the time to transplant the seedlings into a growing medium composed of 40% mature compost, 30% perlite, and 30% coconut fiber. Plant the seedlings 3 cm apart, allowing for about 20 plants to be grouped in a box. The young lettuce will continue to grow for another 25 days. Supplemental lighting should be maintained with watering every 2 or 3 days, depending on conditions.

After a period of acclimatization to outdoor conditions, the lettuce is transplanted into the garden at 30 cm intervals in soil enriched with mature compost. Leaf lettuce will be ready for harvest 40 days later, head lettuce and romaine lettuce at 50 days. The latter are harvested at term while leaf lettuce tolerates gradual harvesting. It is not necessary to have a greenhouse to produce lettuce plants. Sowing in March and April can be done indoors. From the beginning of May, all operations can be carried out outdoors, as lettuce is frost tolerant. Those who prefer direct sowing can sow once a month from the beginning of May, at a rate of one seed every 2 cm in the row. It should then be thinned out to 25 cm.

Continuous harvesting

To enjoy lettuce from June to November, I sow indoors on March 15th for a first transplant in early May. I continue with a sowing in the middle of each month until July 15th, this last sowing ensuring a final transplant of lettuce into the garden in early September.

In autumn, when nights below freezing are forecast, I protect the lettuces from frost with canvas and hoops until late November. At -10°C, I layer up to three canvases. This is when the lettuces become sweetest and crispiest. They provide the gardener in me with an incomparable pleasure.

Greenery lovers can still grow young lettuces under fluorescent lights during the winter. They can be combined with chicory, arugula, and mustard for a greater variety of greens. They can be used to make shimmering winter mescluns that give those who enjoy them an unbearable lightness.