Of all garden vegetables, fresh lettuce offers enough varieties for a new salad every day of the year. Lettuce crops (Lacuca sativa) have been increasing in popularity because the taste of freshly picked lettuce cannot be equaled by lettuce available in supermarkets. Many lettuce varieties are not grown in commercial quantities because greens do not travel or store well.

Greens are high in vitamins A and C, minerals such as calcium and iron and low in calories. Leafy greens are ideal for cool temperatures and short seasons of high altitude gardens because they can be eaten at any stage of maturity. The longer a vegetable is stored, the greater the vitamin loss.

“Greens” is a catch-all title for vegetables that originated from how they are prepared and eaten. Fresh greens include lettuce, spinach, endive, leaf chicory, mache and others that are red in color, like radicchio. Cooked greens include spinach, collard, kale, beet, Swish chard, bok choy, Chinese cabbage, and mustard. Other cultures and countries use pigweed, dandelion and purslane as cooked greens.

Lettuce thrives in average daily temperatures between 60-70 degrees F. High temperatures stunt growth and may cause the leaves to be bitter. Some types and varieties of lettuce withstand heat better than others.

Lettuce has attractive and often colorful foliage. Consider mixing lettuce with flowers for a striking and functional bed or border, rather than planting lettuce in rows in the garden. A lettuce crop is ideal for raised beds — it matures rapidly, can be planted close together and be planted in succession every 7-10 days.

Crisphead is a head lettuce usually started as transplants indoors or in a cold frame. Iceberg is medium size, forming a firm head with a crisp texture, tender hearts and leaf edges tinged light brown. Iceberg is the most commonly grown commercial lettuce variety. Ithaca tolerates heat; resist bitterness and is slow to bolt. Head lettuce usually matures in approximately 70 days.

Butterhead lettuce also forms a head, but the texture is soft and pliable with less distinct veins. Bibb is an heirloom lettuce. Buttercrunch is an American cousin of Bibb, but more tolerant of hot weather (65 days maturity). Marvel of Four Seasons is a popular European variety having green leaves tipped with red. This variety can be planted in late spring as well as late summer and fall (68 days maturity).

Green Leaf varieties include Black-seeded Simpson, the earliest to harvest. Grand Rapids lettuce has frilly edges, and Oak Leaf is resistant to tip burn and good for hot weather.

Red Leaf lettuce includes Red Fire, which has ruffles with red edges and is slow to bolt. Red Sails is the slowest bolting red leaf lettuce. Ruby is the darkest red and resistant to tip burn.

Cos or Romaine lettuces include the Cos type, Cimmaron, that has unique dark red leaves. Green Towers is an early, dark green, large leaf lettuce.

Mesclun is a French name for mixed young leaves for salads. Generally these are harvested while young, so succession planting is essential. Approximately one foot is needed for a salad. Most Mesclun mixes are “cut and come again” varieties, so cutting an inch above the ground with scissors will keep the lettuce growing (35-45 days until maturity).

Plant lettuce seeds ¼ inches deep in rows 12 to 18 inches apart. The soil should be well mixed with organic matter high in nitrogen levels. Thin new seedlings to four inches apart for leaf lettuce and six to eight inches apart for Cos or Butterhead. Transplant Crisphead seedlings ten to 12 inches apart in rows.

Lettuce has shallow roots and needs to be hoed or cultivated carefully. Frequent, light watering causes the leaves to develop rapidly. Overwatering in heavy clay soils can lead to disease, soft growth, scalding or burning of the leaf margins. Organic mulches help moderate soil temperature.
Harvest leaf lettuce when it is large enough to use. The leaves may be picked as needed, allowing lettuce plants to produce more leaves. Crisphead varieties form small, loose heads that weigh four to eight ounces at harvest. Cos varieties have an upright growth habit and form long, medium-dense heads.

It is cost efficient to grow garden lettuce. In addition, natural gardening is important when growing food crops like lettuce. Home gardeners know they will be eating the lettuce they produce and may choose not to use potentially harmful chemicals on their plants. If chemical fertilizers and pesticides are used, read the package instructions carefully before applying them.

For more information on growing leafy greens, please read Colorado State University Fact Sheet #7.608 “Leafy Vegetable Crops.”

The authors have received training through Colorado State University Cooperative Extension's Master Gardener program and is a Master Gardener volunteer for Larimer County.

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This page updated:  May 16, 2007