Harvest romaine when the heads are firm and full-sized, usually 60 to 75 days after planting
Use a clean, sharp knife or garden shears
Cut the whole plant at the base, just above the soil line
Harvest in the morning for the crispest leaves
Remove any damaged outer leaves before cutting
For leaf-by-leaf harvesting, pick the outer leaves first and leave the center to keep growing
Wash the lettuce immediately after harvesting
Store harvested romaine in the refrigerator in a breathable bag or container
Use harvested romaine as soon as possible for the best quality