Corn salad

Valerianella locusta

Vegetable gardenFamily: Caprifoliaceae (Caprifoliacées)Difficulty: Easy

Corn salad (Valerianella locusta) is the winter salad par excellence, and there is probably no vegetable more Belgian for the cold season. While the rest of the vegetable garden sleeps, it forms its small tender rosettes flat against the ground and is harvested from full autumn right through to early spring. It handles frost very well and shrugs off the rain and cold of the Herve region. Its only real fussiness happens at sowing, in late summer, when heat and drought make germination difficult.

Light and exposure

In autumn and winter, give corn salad the brightest spot in the garden. At that time of year the sun sits low and daylight is scarce, and every hour of light counts toward forming nice tight rosettes. An open bed, with no shade cast by a wall or a hedge, suits it perfectly.

August sowings are the exception. Under the still warm late summer sun, an overly scorching position dries out the soil and stops the seeds from germinating. For these first sowings, a corner that gets a little afternoon shade, or a bed shaded by a neighbouring crop still in place, clearly improves emergence.

Watering

The key moment is at emergence. Corn salad seed germinates poorly if the soil dries out, which happens quickly with August and September sowings. After sowing, keep the surface moist with fine, regular watering, in a soft rain, until the young plants are well up. A cloth or a light mulch helps hold that moisture.

Once established and once autumn arrives, corn salad asks for almost nothing. The rains of the Herve region are more than enough, and too much water on cold soil would even be counterproductive. In winter you stop watering and let the sky do the work.

Soil and repotting

Corn salad likes firm soil, rather compact, cool and clean. Unlike many vegetables, it does not need freshly dug and fluffed earth: sow it preferably after an already harvested crop, on soil simply scratched at the surface, then firmed down well after sowing. This close contact between seed and soil encourages germination.

There is no need to manure the bed for it. Soil too rich in nitrogen gives soft leaves that rot more easily in winter. Ordinary earth, neither too acidic nor waterlogged, suits it fine. A former spot for beans or potatoes, cleared of its residue, makes an ideal bed.

Temperature and humidity

This is corn salad’s great strength: cold does not scare it. It grows slowly but surely between 5 and 15 degrees, keeps going under grey weather and withstands sharp frosts, down to -10 or even -15 degrees for the hardy varieties. A touch of frost even firms up its flavour.

Heat, on the other hand, is what bothers it. Above 20 degrees germination becomes unreliable and the plants quickly bolt to flower the following spring. In the cool, damp climate of the Herve region it is therefore perfectly at home, and it really is summer, not winter, that remains its impossible season.

Pruning and upkeep

Corn salad is not pruned in the classic sense, but its upkeep comes down to weeding. Its rosettes are small and low, quickly smothered by weeds. Hoe gently between the rows while the plants are young, without loosening the rosettes, which hold weakly to the soil.

Thin out if the sowing is too dense. Plants that are too crowded lack air, grow leggy and rot faster in damp weather. Leave a few centimetres between each rosette so they form nice round heads and stay healthy all winter.

Pests and diseases

Corn salad has few enemies, which is part of its charm. The main concern is powdery mildew, a white felting that appears when plants are too crowded and poorly aired, especially in a mild, damp late season. Prevention comes down to one thing: sow thinly, or thin out, to let air circulate between the rosettes.

Slugs are the other threat, particularly on the young tender plants in autumn. They can level a sowing in a single night. Collecting them in the evening, dry ash or mulch around the beds, and keeping watch after each gentle rain limit the damage. Rot can also affect rosettes in contact with waterlogged soil: well-drained earth and a not too dense sowing prevent it.

Propagation

Corn salad is grown solely from direct sowing in place, shallow. Sow on the surface or barely covered, under just a few millimetres of fine soil, then firm down hard with the back of a rake or a small board. This firming is essential: it ensures the seed-to-soil contact that triggers germination. Then keep moist until emergence, which takes one to three weeks depending on the warmth.

To save your own seed, let a few plants bolt to flower in spring. Corn salad flowers in small bluish clusters and readily self-seeds around the garden on its own. Harvest the seeds when they turn brown, dry them and keep them dry: they hold their germinating power for several years.

Local know-how

In Belgium (Herve climate, zone 8a)

Corn salad is made for the climate of the Herve region. Where most salads fear the cold, it makes it an ally: it occupies the garden during the months when nothing else grows and offers fresh greens from November right up to the first days of March.

The schedule fits in one sentence: you sow from late August to October, you harvest from autumn to early spring. The August sowing is the trickiest, because the heat and drought of late summer make the seed germinate poorly. The trick is to water finely and regularly, to sow in partial shade or under cloth, and to firm down well. September and October sowings come up more easily, on soil that is cooling down. Once autumn passes, corn salad takes the frost head-on: there is no need to protect it, though a simple winter fleece keeps the foliage cleaner and makes picking easier in frosty weather. You harvest as needed, cutting the whole rosette at the collar, just above the soil. It is one of the few fresh vegetables of the Belgian garden in the dead of winter, and it asks for almost no care once established.

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Month-by-month care calendar

JanuaryHarvesting in the depths of winter. Cut the rosettes at the collar as needed, even in frosty weather. Under fleece the foliage stays cleaner.
FebruaryContinuing the harvest of the autumn sowings. The rosettes firm up in the cold. Plan out the freed-up beds for spring.
MarchLast harvests before bolting. Possibility of a spring sowing on warming soil, for a quick harvest before the heat.
AprilHarvesting the March sowings. Optionally let a few plants bolt to flower to save your own seed.
MayEnd of the season’s corn salad. The plants flower and self-seed. Harvest the seed from the finest plants when it turns brown.
JuneRest time for corn salad, heat does not suit it. The bed can host a summer crop while waiting for the late-season sowings.
JulyNothing to sow, it is too hot. Prepare and mark out the beds that will be freed up in August for the future sowings.
AugustFirst sowings in place, in partial shade. Water finely and regularly, firm down well: this is the trickiest emergence of the year.
SeptemberPeak sowing period. The soil cools down and germination becomes easier. Thin out and weed the August sowings.
OctoberLast sowings of the season. First harvests from the August sowings. Watch for slugs on the young tender plants.
NovemberFull harvest of the well-formed rosettes. A winter fleece keeps the foliage clean and makes picking easier.
DecemberHarvesting as needed. Corn salad takes the frost without damage. Cut at the collar and rinse well after picking.

Green Hub tips

  • The secret of the August sowing is moisture: water fine and often, sow in partial shade and firm down hard, otherwise the seed will not come up.
  • Sow thinly or thin out. Rosettes that are too crowded smother themselves, catch powdery mildew and rot as soon as the weather turns mild and damp.
  • A touch of frost firms up the flavour of corn salad: no need to protect it, it is a genuine fresh vegetable of deep winter.
  • Harvest by cutting the whole rosette level with the collar, and rinse carefully: the low leaves easily hold on to soil.