Growing lettuce for springtime salads is irresistible. But what if you could pick homegrown lettuce now through fall, without taking a break during the hot summer months when the plants tend to turn bitter and go to seed? Impossible, you say? Not if you follow our plan. We investigated the latest lettuce research, interviewed expert growers, and came up with a strategy that promises to keep your salad bowl full of frilly looseleafs, tender butterheads, flavorful Batavians, crispy romaines, and delicate baby greens every week of the gardening season.
Let's start with a quick review of the different types of lettuce, how long they take to mature, and their tolerance for hot temperatures and long days. With this information, you can choose the right varieties for your garden in spring, summer, and fall.
Looseleaf lettuces don't form a head but grow into clusters of frilly, smooth, or lobed leaves in a range of colors. They mature in about 50 days but can be harvested in as little as 30 (if you pick them at the baby stage). Looseleafs generally fare best in cooler weather, so plan to grow them in spring or fall. They hold up to hot summer weather much better as baby greens than as mature plants.
Butterhead, also known as Bibb and Boston lettuce, forms crumpled-looking heads with tender, dark green outer leaves and crunchy, light-colored hearts. Harvest butterheads when the inner leaves form a loose head, about 60 days after planting. Some butterheads, notably 'Butter-crunch' and 'Optima', hold well in hot weather, but this group typically does best in spring and fall.
Romaine varieties form upright heads with dark green or red-tinged outer leaves and crisp, whitish hearts. Green romaines, particularly 'Jericho' and 'Green Towers', handle heat with aplomb, but red romaines tend to produce open heads and bolt in summer. Romaines take between 55 and 65 days to mature, but baby romaine leaves can be harvested in less than a month.
Batavian lettuce's shiny leaves mature into loose, whorled heads with crisp hearts. At Colorado State University, researchers evaluated the bolting resistance of dozens of lettuce varieties and reported that Batavians stayed crisp and tasty in heat and resisted going to seed longer than any other type of lettuce--in some cases holding for more than 100 days during the height of summer.
Crisphead lettuces, also known as iceberg, grow slowly—maturing in about 75 days--and produce very round, crunchy, pale green heads. While crispheads are known for their resistance to bolting in hot weather, they are prone to internal tip burn during summer and produce the best-quality heads in spring and fall.