Does Lettuce Need to be protected from Frost?
Growing your own lettuce is a beautiful thing. Not only is it rewarding to pick your own fresh produce, but once picked, lettuce will continue to grow, giving you successive harvests of fresh greens. But what happens when temperatures dip toward the freezing mark? Does your lettuce need to be protected from frost? Lettuce seedlings will generally tolerate a light frost and, unlike most vegetables, continue to grow through the fall when the possibility is a probability in some regions. That said, cold, clear nights may create frost damage in lettuce, especially if the duration of the cold snap is lengthy.
Lettuce and Frost Resulting Symptoms
Frost damage in lettuce causes a variety of symptoms relating to the severity and length of the freezing period. A common symptom is when the outer cuticle of the leaf separates from the underlying tissue, causing a bronzed color due to the death of those epidermal cells. Severe damage causes necrotic lesions of the leaf veins and spotting of the leaf, similar to pesticide burn or heat damage. On occasion, the tips of young leaves are killed outright or frost damages the edges, resulting in the thickening of the leaf tissue. Any damage to lettuce due to frost should be removed or the plants will begin to decay and become inedible.
Lettuce and Frost Protection
Lettuce is tolerant of cold temperatures for short periods of time, although growth will slow down. To protect lettuce in frost-prone areas, plant romaine or butterhead lettuce, which are the most cold-tolerant. When frost is predicted, cover the garden with sheets or towels to provide some protection. This will help in the short term, but if prolonged frost is due, your lettuce is likely in jeopardy. Finally, outdoor freezes may not be the only concern for lettuce and frost. Frosty conditions in your refrigerator will definitely damage the tender lettuce greens, leaving you with a slimy mess. Obviously, don’t put lettuce in the freezer. Adjust the setting of your fridge if it is prone to frosting up.
