Q&A: Dry Leaf Tips
Question: I have corn plants (Dracaena fragrans 'Massangeana') that seem to be growing well except that the tips and sides of some of the leaves turn brown and dry. This happens not only to the lower leaves but to the top leaves as well.
Answer: This leaf scorch can be caused by fluoride toxicity or by excessive salts in the potting medium. Dracaenas and other plants in the agave family are sensitive to fluoridated water. Maintaining a medium pH between 6.5 and 7.0 should alleviate this injury by making fluoride less available to the plant.
Excessive salt buildup comes from fertilizing and watering. When the water evaporates, salts such as sodium chloride, calcium carbonate, and iron sulfide remain and collect over time. To reduce this buildup, flush the soil periodically by watering until water flows from the drainage holes. However, never let your plant stand in the resulting pool of water.