This delay adds to the succession process. As the plants enlarge, it is a common practice to harvest every other one as needed, thus giving those remaining more growing room. Pests Lettuce is susceptible to a few pests that can be real nuisances in the home garden. Slugs and snails can wreak havoc overnight, especially when seedlings are young and tender. Hand picking and clean garden practices are the first line of defense.
Birds can decimate a lettuce patch, and they like the same tender seedlings as do the slugs.
Aphids, white flies and leafhoppers sometimes become lettuce pests, not only for the damage they do to the plants, but also for the crippling plant virus diseases they carry. Sometimes aphids can be washed off with a stiff spray of water, or use a homemade garlic spray. Ladybugs and lacewings eat these pests, so encourage them in your garden. Cabbage looper worms and other larvae can be destructive, but often there isn't a big enough infestation to require anything but hand picking. For these chewing pests there are safe biological controls if your garden becomes overrun.