Romaine lettuce, a variety of cos lettuce, is a popular garden crop known for its crisp texture and slightly sweet flavor. Unlike butterhead or loose-leaf varieties, Romaine forms an elongated, upright head, requiring a distinct harvest method. Knowing when and how to cut this lettuce ensures you maximize both the flavor and the total yield across the growing season. The goal is to collect mature leaves while encouraging the plant to continue its growth cycle.
Determining Harvest Readiness
The timing of the harvest is linked to the quality and tenderness of the Romaine leaves. A typical plant is ready for its first significant harvest between 60 and 75 days after planting, though this varies by cultivar. When mature, the heads should be full, vibrant, deep green, and six to eight inches tall. The internal leaves will naturally be lighter in color and more tender than the outer foliage.
Check the seed packet for the specific “days to maturity” listed for your variety, which provides a general timeframe for monitoring. Avoid waiting until the leaves begin to yellow or the central stalk starts to elongate. This signals the plant is preparing to “bolt,” which causes the leaves to become bitter.
The ideal time of day for cutting lettuce is mid-morning, after the dew has dried but before the heat sets in. Harvesting in the morning ensures the leaves are at their crispest because the plant has spent the night absorbing water. Picking the leaves when they are dry also minimizes bruising and reduces the risk of spoilage after storage.
Specific Methods for Cutting Romaine
Gardeners generally employ two distinct techniques for harvesting Romaine, depending on whether they desire a single large harvest or a continuous supply. The “cut-and-come-again” method allows for multiple harvests from a single plant throughout the season.
Cut-and-Come-Again Method
To use this technique, selectively remove the largest, outermost leaves while leaving the central growing point, or heart, intact. Use a sharp, clean pair of scissors, shears, or a knife to make a precise cut near the base of the leaf, about one inch from the plant stem. This focuses the plant’s energy toward the center, promoting the growth of new, tender leaves from the crown. Harvest no more than one-third of the total leaves at any one time to ensure the plant has enough foliage for photosynthesis and quick recovery.
Full Head Harvesting
This technique is used when collecting the entire mature head at once. Use a clean, sharp knife to make a single, horizontal cut across the base of the plant. The cut should be made approximately one to two inches above the soil line. Leaving this base allows the potential for a small, secondary head to regrow, offering a bonus harvest before the season ends.
Post-Harvest Handling and Storage
Immediate and proper handling after cutting is necessary to preserve the crispness and flavor of the leaves. Once harvested, the leaves should be cooled quickly to halt respiration and slow wilting. A gentle rinse in cold water is sufficient to remove any residual soil or debris.
Avoid using a forceful stream of water, which can bruise the leaves. Thoroughly drying the leaves is a crucial step before storage, as excess moisture accelerates decay. A salad spinner effectively removes water, or you can gently pat the leaves dry with clean paper or cloth towels.
The optimal storage temperature for Romaine is near 32 degrees Fahrenheit, which can extend its shelf life to about three weeks. To replicate this in a home refrigerator, store the dry leaves in a high-humidity crisper drawer, kept separate from ethylene-producing fruits like apples or bananas. Placing the leaves loosely wrapped in a damp paper towel inside a perforated plastic bag or an airtight container helps maintain the high humidity required to prevent water loss.
Ensuring Future Yields
Continued garden care promotes new growth when using the cut-and-come-again method or harvesting the full head above the soil line. After cutting, the remaining plant base requires consistent moisture to fuel its regrowth. Watering should be light but frequent, ensuring the soil remains evenly moist without becoming waterlogged.
The plant utilizes its stored energy to generate new leaves from the central crown. This process can be supported with a light application of a balanced, water-soluble fertilizer if soil nutrients are depleted. Protecting the remaining plants from heat is also important, as high temperatures trigger the plant to bolt and turn bitter. Using a shade cloth during the warmest part of the day can help keep the plant cooler, extending the harvest window and encouraging subsequent flushes of tender leaves.