Wilted, yellowed lettuce makes for a disappointing salad. Keep your greens fresh longer by storing them properly. Heavy moisture and warm temperatures hasten spoilage, so keep stored lettuce cool and only slightly moist.
Excessive moisture encourages lettuce to rot. Dry off the leaves of your greens before packing them in a plastic bag. Make sure the bag is also free of visible moisture and sealed loosely so all the leaves are covered.
A paper towel placed in the bag with the greens helps absorb extra moisture. The paper towel may also be used to promote a bit of humidity, which gives you crisp lettuce leaves. Dampen the towel lightly and wrap the head of lettuce with it. Make sure all excess moisture is wrung out first, though.
Avoid washing lettuce until the day you plan to use it. If you prefer the convenience of prewashed lettuce, you can tear up the leaves, then wash and dry them thoroughly. Place the lettuce in a zip-top plastic bag that you've lined with paper towels, and seal it tightly. The lettuce will stay fresh for just a day or two with this method, while unwashed it can stay fresh three to four days.
Keep your lettuce apart from fruit, which emits gases that hasten spoiling. Place it in a cold spot in your refrigerator, but not so cold that it freezes the leaves. Delicate micro greens, baby lettuce and butter lettuce may spoil more quickly than heartier lettuce varieties, including romaine and iceberg. Your best bet is to use lettuce within a few days of bringing it home from the market or harvesting it from your garden.