How to prune cos romaine lettuce

Harvest outer leaves from 5–6 weeks; cut full heads at 10–12 weeks or before bolting in warm weather. For outer-leaf harvest, snap leaves cleanly at the base, leaving the growing point intact. For full-head harvest, cut the plant at soil level with a sharp knife. Remove yellowed, damaged, or diseased outer leaves promptly throughout the growing period.

As needed; harvest-driven. Cos Romaine can be harvested as full heads or by cut-and-come-again outer-leaf removal. No structural pruning is required. Remove yellowing outer leaves to maintain airflow and reduce disease. Harvest whole heads when leaves are upright and the heart is well-formed. Bolting makes leaves bitter — harvest promptly in warm spells.

For outer-leaf harvest, snap leaves cleanly at the base, leaving the growing point intact. For full-head harvest, cut the plant at soil level with a sharp knife. Remove yellowed, damaged, or diseased outer leaves promptly throughout the growing period.