My
peace lily leaves are all brown on the edges.
Drought
stress is usually the cause of this problem with peace lilies (Spathiphyllum). Keep the soil slightly moist to prevent wilting and
browning. Peace lilies will let
you know by their drooping leaves that you waited too long to water. They usually recover but at some point
the plants start permanently wilting and the leaf margins start to brown. Try to water just before the leaves wilt. Over watering causes the same
problem. Adjust your watering
schedule to fit the growing conditions.
Water thoroughly and often enough to keep the top several inches of the
soil moist but not wet.