A lettuce plant can generally be harvested multiple times after cutting. This method, known as “cut-and-come-again,” allows for an extended harvest of fresh greens from a single plant. Success relies on understanding the lettuce plant’s biology and applying precise harvesting techniques to encourage continuous leaf production.
The Mechanism of Regrowth
New growth originates from a specialized area of cells located at the base of the plant known as the shoot apical meristem. This dome-shaped structure, often called the crown or growing point, contains a population of stem cells that continuously produce new leaves and tissues. When the outer leaves are removed, the plant is signaled to continue its growth cycle, provided the apical meristem remains undamaged and intact. The remaining lower leaves and the stump contain stored energy reserves, primarily carbohydrates, which fuel the rapid development of new leaves from the meristem. This biological process allows the plant to quickly regenerate the harvested foliage, often providing a new supply of leaves every two to three weeks.
Harvesting Techniques for Successful Regrowth
To successfully engage the cut-and-come-again method, the harvest must be executed with precision. The primary goal is to remove the outer, mature leaves without damaging the central growing point. The most effective approach involves using clean, sharp scissors or a knife to snip the leaves one to two inches above the soil line. This cutting height ensures the delicate apical meristem, which is located low in the center of the plant, is left unharmed.
Alternatively, you can harvest individual outer leaves from the plant, leaving the four to six small inner leaves to continue expanding. Removing the outer leaves first also helps expose the inner leaves to light, which promotes faster growth.
After harvesting, the remaining plant base needs continued moisture and care to regenerate efficiently. Watering the plant immediately after cutting helps it recover from the stress of the harvest and supports the new cellular division within the meristem. Consistent watering and protection from intense heat will encourage the stump to produce its next flush of leaves instead of prematurely sending up a flower stalk, a process called bolting.
Varieties Best Suited for Cut-and-Come-Again
Loose-leaf varieties are significantly better suited for the cut-and-come-again method because their growth habit naturally keeps the growing point exposed. These types do not form a dense, single head, making it easier to harvest leaves without destroying the central crown.
Excellent choices for multiple harvests include many loose-leaf cultivars such as Black Seeded Simpson, Salad Bowl, Oakleaf, and the various Romaine and Butterhead types. These varieties are often more tolerant of heat and slower to bolt than other types, extending the harvest period.
In contrast, heading varieties, like Iceberg and most crisphead lettuces, are designed for a single harvest. Removing the entire head of these varieties usually removes the entire apical meristem, preventing any subsequent regrowth.