It is related to stress, but stress is a very broad term used to describe a plant that is operating at or very near the limits it was genetically programmed to deal with. The burned leaf tips or margins indicate the plant cannot move water to its distal parts fast enough to prevent those tissues from dying. The usual suspects are over-watering, which compromises root function and inhibits the plant's ability to move water, and a high level of salts in the soil, which can make it difficult for the plant to take up water. Often a combination of these factors combine to make it difficult for the plant to move water efficiently enough to prevent the burned tips/margins.

Sometimes, plants are sensitive to elements/compounds in water, like fluorine or chlorine, but studies show that in most cases, these influences are taking the rap for something that more rightly belongs at the feet of one of the issues mentioned previously. The condition can be exacerbated by low humidity, but the way you can do the most good is by making sure you provide a healthy root environment. Soils that allow you to water properly and will stay well aerated even after you flush the soil are going to have the most significant impact on correcting the problem, just as poor soils that do NOT allow you to water properly are the most significant contributors.

Raising the humidity around the plant, preferably in the whole room, is also very helpful. Misting will NOT make any evident contribution toward eliminating the problem.

If you want to look deeper into ways that will allow you to water correctly, just ask. Adopting a healthy soil is the best way, but short of that, there are still other things that can be done to help ameliorate these unwanted symptoms.

Al

Wendy..can you post a few pics w/brown leaf tips?