Tip burn is a physiological disorder in leafy crops β most commonly lettuce β where the edges and tips of inner leaves turn brown and die. It is caused by calcium deficiency at the leaf margins, not from a lack of calcium in the nutrient solution, but from inadequate calcium transport due to low transpiration inside dense, enclosed leaf heads.
Key Facts
- Caused by calcium deficiency at the leaf tip β calcium transport requires transpiration
- Common in fast-growing, densely headed lettuces: butterhead, romaine, Boston types
- Occurs even when reservoir calcium levels are adequate
- Triggered by low VPD, high humidity, and insufficient airflow across the canopy
- Prevention: increase airflow, reduce humidity, space plants wider, use oscillating fans
- Some lettuce varieties are genetically tip-burn resistant β choose these for dense systems