I am growing Flashy Trout Back lettuce for the first time and I love the way the leaves are emerging with wine-colored speckles. Makes it easy to distinguish from spring weeds. Flashy Trout Back is an heirloom European lettuce dating back to the 1700s. Known as “Forellenschuss’ or trout speckles, the leaves are supposed to look like the back of trout fish. The wine-colored spots against the bright green leaves add color in my garden, where for now they receive full sun but cool spring temperatures. In the summer, I will grow lettuce in the backyard where the delicate leaves will receive dappled sun or shade from the tall summer vegetables. Lettuce likes rich soil, cool weather, a regular supply of moisture, and here in Northern Virginia, full sun in the spring and afternoon shade in the summer. We can sow seeds outdoors as early as mid to late March, and continue to sow every couple of weeks until the heat of the summer kicks in. Lettuce seed can germinate at temperatures as low as 40 but best at 75 and poorly at 80-85 degrees F.
Flashy Trout Back is a romaine (also known as cos) type of lettuce, considered the most nutritious of the different types of lettuce, followed by loose leaf, which is a non-heading type that comes in various shades of green or red. Third in nutrition is bibb or butterhead, a heading lettuce with looser and darker green leaves than iceburg, and fourth is crisphead, a tight heading type with light green leaves (e.g., iceburg). Romaine has a stiff, vertical shape that is great for wraps, fajitas, sandwiches, and, if cut up, salads.
In the lettuce world, the Holy Grail is a lettuce that tolerates the heat in the summer and resists bolting which is why you may find terms such as “heat-resistant” and/or “slow-bolting” in catalogs and on seed packets. Bolting is when the lettuce starts to flower. In other words, the plant stops putting energy in to leaves and starts to send up a flower stalk in order to flower, set seed, and die. This occurs with increased temperatures and day length. Resistance to bolting is highest with loose leaf lettuce, followed by romaine, bibb (butterhead), and crisphead. If you want to continue to grow lettuce in the summer, you need to look for heat resistant, slow-bolting types and provide continued moisture and shade.
Always harvest lettuce in the early morning, when the leaves are full of water and the glucose content is highest. Also, the outer leaves of leaf lettuce contain higher levels of calcium so harvest the outer leaves first on the Romaine and the loose leaf types. Know that lettuce tends to get small bugs like aphids so after you cut the leaves, wash them and let them soak in a large bowl of cold water for about 20 minutes, and then use a salad spinner.