Gardeners can select from a large variety of lettuces that are easy to grow, highly productive in limited space, and virtually pest and disease free. Lettuce is definitely one of the more “care-free” crops. For maximum lettuce production, it’s wise to select a site where the soil drains well, yet retains some moisture. The soil should also be rich in nitrogen and potassium, The best way to accomplish this is to work in plenty of organic matter (compost, rotted manure, or leaf mold) that will loosen and enrich the soil. Strive for a pH of 6.0 to 6.8. Most lettuce varieties mature in 45 to 55 days, allowing many gardeners to plant two or even three crops. But looseleaf and butterhead leaves can be harvested at just about any time in their development. Heading varieties take longer to mature. Romaine takes 75 to 85 days and crisphead 70 to 100 days. By choosing the right varieties, it’s possible to have lettuce in your garden throughout the growing season.
Source: The Cook’s Garden