Mâche (Corn Salad)

Sow the main fall crop once the soil cools

Direct seed a quarter inch deep once soil temperature has dropped into the 41 to 68F range, thinning later to 3 to 4 inches apart in rows 12 inches apart. Sow again every two weeks for a continuous supply, and keep the seedbed damp because germination is slow. Mache seed goes dormant above 70F, so a sowing made into warm soil simply sits and fails rather than germinating unevenly. Cool soil is the trigger, not the calendar.

Sow a spring crop three to four weeks before your last frost

Direct seed a quarter inch deep three to four weeks before your average last spring frost, or set out transplants that have been grown for five to six weeks and carry 4 to 6 mature leaves. Sow every two weeks until soil warms past 68F. Mache tolerates frost at the seedling stage and stops growing well once temperatures pass 75F, so the spring crop has to be started early enough to size up and be eaten before heat arrives.

Water 1 to 2 inches a week at soil level

Give 1 to 2 inches of water per week, ideally by drip rather than overhead sprinkling, and mulch to hold that moisture. Aim for steady damp rather than a wet-then-dry swing. Wet foliage is what lets Alternaria leaf spot establish and what favors damping-off in a crowded seedbed, and a rosette this close to the ground dries slowly once the leaves are soaked.

One light nitrogen feeding at thinning

At thinning, or about four weeks after transplanting, side-dress a quarter cup of a nitrogen fertilizer such as 21-0-0 per 10 feet of row and water it in. If you feed with compost instead, apply no more than an inch of well-composted organic matter over the area before planting, and stop there. Mache is a small, fast leaf crop that feeds lightly. A single measured nitrogen push once the plants are established carries the rosettes to size without pushing soft growth into winter.

Thin to 3 to 4 inches once seedlings have true leaves

When seedlings have three to four true leaves, thin them to 3 to 4 inches apart in the row. The plants you pull are not waste - transplant them to fill gaps or eat them as they are. Mache grows as a low rosette only 2 to 5 inches tall, so crowded plants shade each other out and trap moisture in the crowns where rot starts.

Scout for aphids, flea beetles and slugs in the rosettes

Check the undersides of leaves and the center of each rosette for aphids, flea beetles, leaf miners, cabbage loopers and slugs. Floating row covers exclude most of them outright. If aphids build up, insecticidal soap at a 1 to 2 percent solution works, but only where the spray actually lands - hit the leaf undersides and repeat every 4 to 7 days until they are gone. Insecticidal soap kills soft-bodied insects by disrupting their cell membranes and stripping their protective wax on contact, and it leaves no residue behind, so pests that were missed or that hatch afterward are untouched.

⚠ Insecticidal soap can be used on vegetables right up to harvest, but do not apply it in full sun or above 90F - it will burn the foliage. Do not spray plants that have bolted into flower; the soap kills any soft-bodied insect it contacts, pollinators included.

Mulch heavily for winter once plants carry 4 to 5 true leaves

Once the plants have four to five true leaves, cover them with a heavy mulch of straw or evergreen boughs to carry them through winter, and pull that mulch back once the snow melts in spring. A floating row cover handles the lighter frosts of spring and fall on its own. Plants that go into winter at the four-to-five-leaf stage have enough root to survive and enough crown to resume growth, which is why mache can be cut in the dead of winter when nothing else is standing. Temperatures down to 32F do not seriously damage young plants.

⚠ Leaving the mulch on past snowmelt smothers the crowns just as they resume growth - pull it back promptly.

Cut whole rosettes, and finish before spring warmth bolts them

Harvest starts two to three weeks after emergence or transplanting. Either cut individual leaves with scissors at about 4 inches across, which lets new leaves regrow from the center, or cut the whole plant at the root when the rosette is 2 to 3 inches tall. Refrigerated, it holds five to seven days. Mache bolts as soon as spring weather warms, and once it sends up a seed stalk the rosette turns bitter and the harvest is over. Cutting whole rosettes is also the fastest way to clear a bed for the next crop.