Few things beat a salad made from a large handful of fresh lettuce (Lactuca sativa var. capitata) straight from the garden. While you can allow both loose-leaf and head-style lettuce plants to reach full size in the garden, then pull or cut them at the roots to harvest a whole lettuce, growing lettuce lets you prolong the season by cutting it leaf by leaf or using a technique called cut-and-come-again.
Leaf by Leaf Cutting
You can cut leaves of edible size from the stem of the plant, leaving the small-leaved center intact and growing. Leaves can be pinched off by hand, but cutting may damage less tissue than pinching. Wipe the scissor blades clean between cuts with a 1:9 solution of bleach and water, to keep from spreading plant diseases. A 1/3 cup of bleach in 3 cups of water will keep tools clean for cutting and other garden chores.
The second cutting method is more drastic but still allows the plant to continue growing. For cut-and-come-again, cut the entire plant parallel to the ground and approximately 1 inch from the soil. The center will regenerate first, and the plant will then begin to form new leaves that grow to edible size. Clean your tools before cutting each plant.
Lettuces for Leaf-by-Leaf Cutting
Loose-head, or loose-leaf, varieties are best for leaf-by-leaf cutting. Grand Rapids varieties like "Red Sails" and "Black-Seeded Simpson" have broad, ruffled leaves. Lobed-leaf varieties, commonly dubbed "oakleaf," also have large, loose clusters of leaves, making removal of a leaf or two easy. Planting a loose-head variety in a large pot lets you rotate the pot, gathering leaves from all the way around the plant. Because the stem lengthens as lettuce grows toward blooming and going to seed, or "bolting," your remaining plant may vaguely resemble a palm tree, but the leaves will remain sweet so long as temperatures stay below 75 to 80 degrees Fahrenheit.
Cutting the whole plant down to 1 inch yields a large harvest of loose-head leaves. You can harvest like this two to three times before the quality of the leaves declines. Butterhead and Romaine lettuce varieties can also be cut down to 1 inch, but the remaining stubs often generate a less vigorous but edible second growth.
Cutting and Timing
Both cutting methods work best when carefully timed. Although it may take a little practice from one variety to another, leaves that are just getting crisp and starting to look mature are ready for cutting. Old leaves will have poor or bitter flavor, no matter how they are harvested. The time of day can have a significant effect on the quality of the lettuce leaves. Leaves harvested early in the morning, around 7 a.m., contain approximately twice the plant sugars of leaves harvested at 2 p.m. Cut early for a sweet harvest. Early morning cutting also lets plant wounds begin to heal before exposure to hot sun threatens to scorch tissues.