Lettuce
Lettuce, a cool-season vegetable, is one of the easiest crops to grow. Lettuce withstands light frost; however, sunlight and high summer temperatures usually cause seedstalk formation (bolting) and bitter flavor. Slow-bolting or heat resistant varieties are available and are recommended to extend the lettuce-growing season. Several types of lettuce are commonly grown in home gardens. Details of each type follows. Crisphead, also known as iceberg, is the most widely-available, fresh market type of lettuce. It has a tightly-compacted head with crisp, light green leaves. Many gardeners find this type difficult to grow because it requires a long season and because some of the most advertised varieties are not heat resistant and tend to go to seed as soon as temperatures rise. For best results, select a slow-bolting variety and start seed indoors in late winter or late summer. Transplant in early spring or fall to take advantage of cool weather. Mulch well to keep soil temperatures from fluctuating and to hold in moisture. An organic mulch is more suitable than black plastic after soil temperatures rise. Mulching also keeps soil off the leaves, reducing chances of disease from soil borne organisms. Butterhead or bibb lettuce is a loose-headed type with dark green leaves that are somewhat thicker than iceberg lettuce leaves. Butterheads have a light yellow, buttery appearance and are very attractive in salads. A miniature butterhead variety, 'Tom Thumb', requires a short growing time and is very easy to grow. One head of this lettuce provides about one or two servings. It can be planted in succession about 2 weeks apart, or it can be started indoors for an even longer season. However, if temperatures become too high, bibb lettuce will become bitter. Romaine or cos red leaves. It is a fast-growing, long-lasting lettuce often lettuce is less frequently grown by home gardeners, but it is a very nutritious lettuce that deserves attention. It is also relatively easy to grow, forming upright heads with slightly wavy, attractive leaves. Leaf lettuce is popular among home gardeners and may be used in salads, sandwiches and wilted lettuce salads. Sow leaf varieties in rows, 10 to 20 seeds per foot with rows spaced 8 to 12 inches apart. Thin individual plants to 4 to 8 inches apart, depending on variety. Leaf lettuce also grows successfully in wide bed arrangements. Seedlings are thinned to 4 to 8 inches on all sides. Cos and head types should be sown or transplanted 12 to 18 inches apart. If in rows, allow 30 inches between rows. Cultivate carefully as lettuce is shallow-rooted. Use frequent, light waterings to encourage rapid growth, but do not over water as this may cause root or leaf diseases. Overhead watering should always be done in the morning so that plants will dry before nightfall. Mulches are helpful in maintaining soil moisture and keeping leaves off the ground. Lettuce planted in very early spring should be given full sun so that the soil will be warm enough for rapid growth. For long-season lettuces, plant so that other crops, such as sweet corn staked tomatoes, pole beans or deciduous trees, shade the lettuce during the hottest part of the day. Interplanting helps to make the most of garden space; plant lettuce between rows or within a row of later-maturing crops like tomatoes, broccoli or Brussels sprouts. Some lettuces like 'Tom Thumb' and leaf lettuces are attractive in flower borders. It is best to plant lettuce in succession or to use different varieties that mature at different times. Thirty heads of iceberg lettuce harvested at once can present a major storage problem! Leaf and bibb lettuces do well in hotbeds or greenhouses during winter and in coldframes in spring and late fall. Common Problems
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