Growing Salad Greens

In Sonoma County, with the right gardening practices and crop variety selections, it’s possible to harvest salad greens 12 months of the year. Refer to the Vegetable Planting Summary link and others below for details about planting times, growing conditions, and characteristics of many leafy greens.

Choices

• For a mix of textures, flavors, and colors, plant a variety of lettuces and other greens such as arugula, curly endive, escarole, radicchio, mâche, spinach, watercress; and Asian greens such as mizuna, tatsoi, bok choy, looseleaf Chinese cabbage, komatsuma, and mustard. Some seed companies sell salad mixes such as mild, piquant, French, Italian, and others.
• Seasonal weather influences crop and variety selection. Fall selection depends on whether the crop will be harvested in fall, winter, and/or early spring. Some crops, such as lettuce, are semi-hardy (able to survive a light frost) while others, such as spinach and kale, are cold-hardy (able to survive a hard freeze). If growing salad greens in warm weather, select slow-bolting or heat-tolerant varieties. (See the Master Gardener Vegetable Planting Summary link below.)

Planting

• Most crops can be planted February-October. If planted in well-draining soil, lettuce can be brought to maturity during fall for harvest over a mild winter. Lettuce and several other leafy greens will overwinter, but head lettuce is best planted only in early spring.
• Direct-seeded plants may also be started in containers and set out in the garden when seedlings have at least two sets of true leaves.
• For a winter harvest, direct sow or transplant greens allowing enough time to bring them to maturity by either the first average frost/freeze date or November 18—whichever occurs first. At Sonoma County’s latitude, November 18 is the last day with at least ten hours of daylight; plant growth slows significantly or stops with less than ten hours of sunlight. (See link below.)
• Direct seeded cool-weather leafy greens prefer warm soil, 60-65 degrees, and warm air, 65-75 degrees, for germination. Transplants can tolerate soil temperatures as low as 40 degrees.
• To protect greens in warm weather, plant on the north or east side of a structure for protection from hot afternoon sun or where they will be shaded by taller or trellised warm-weather crops.

Growing Conditions

• Salad greens grow best in fertile soil with good quality compost added for adequate nutrition.
• Fast-growing and shallow-rooted greens require regular moisture but not wet soil. Inadequate irrigation may cause bolting (going to seed) and tough and bitter leaves. A mulch of rice straw, shredded leaves, or other organic material retains soil moisture and suppresses weeds that compete for water, nutrients, and light.
• Thin seedlings of direct-sown seeds when they are 3-4 in. tall. Cut plants off at ground level to avoid disturbing roots of plants that are left to grow. Use thinnings in salads. Or thin by transplanting into rows, leaving 8-12 in. between rows.

Protection

• Most salad greens tolerate light frosts with no protection but no not tolerate freezing temperatures. Depending on a plant’s cold-hardiness, construct a cold frame, use a floating row cover such as Reemay, or drape frost cloth or bed sheets on supports, securing cloth to the ground. Open the cold frame or remove cloth on sunny winter days.
• Greens grown during the cool season have few pests except for snails and slugs. Control them by hand-picking or with baits or traps.
• During the warm season, greens are subject to attack by flea beetles, leaf miners, and, for greens in the Brassica (cabbage) family, cabbageworms. Seedlings are the most likely to be seriously damaged. Protect them with a floating row cover whose edges are firmly held down, or germinate seeds in a greenhouse or indoors. Or avoid the problem altogether by not growing greens during summer. See UC’s Integrated Pest Management (IPM) link below.

Harvest

• When harvesting leaf lettuce and other leafy greens, remove the entire plant or use the cut-and-come-again method: when leaves are 3-4-in. tall, cut them off without harming the crown of the plant, leaving 1-2 in. on the plant. New leaves will grow from the crown. Plants can be cut 3-4 times. When removing spent plants, cut at soil level, leaving roots in the soil for added organic matter and minimal soil disturbance.
• Harvest small, tender greens for salads. When larger, cook them in dishes such as stir fries.

Containers

• Lettuces and other salad greens also grow easily in containers 10-18-in. wide and 8 in. deep with drainage. A 6-in. depth is sufficient for leaf lettuce. Fill containers with a purchased, organic potting mix.
• Small containers can be moved to protect greens from afternoon sun during warm months or from hard freezes or heavy downpours during cool months, or to take advantage of daylight as the fall and winter sun becomes lower in the sky.

Additional Information

• Sonoma County Master Gardener Vegetable Planting Summary.
• https://sonomamg.ucanr.edu/Food_Gardening_Articles/
• http://ipm.ucanr.edu/home-and-landscape/lettuce/index.html
• http://ipm.ucanr.edu/PMG/GARDEN/veggies.html
• http://ipm.ucanr.edu/QT/snailsslugscard.html
• https://sonomamg.ucanr.edu/files/272994.pdf (1st & last frost dates)

April 2022