Tipburn is a physiological disorder that affects plants such as lettuce and spinach. The tips of the leaves are brown. The necrosis may involve a few spots along the margin or the whole edge of the leaf may be affected. The lesions are frequently invaded by soft-rotting bacteria that can cause severe decay. On lettuce, symptoms are not usually visible from the outside of the plant, but if you break open an affected head, you will see that the edges of the internal leaves are brown.
Solutions
Tipburn is related to calcium deficiency and aggravated by high soil fertility and high temperatures. Hold nitrogen levels as low as possible, and do not apply excessive fertilizers that might compete with calcium uptake. Follow good irrigation practices and avoid water stress.
