I have a VERY big, once beautiful, peace lily whose leaves are turning dark brown. The discoloration begins at the edge of the leaf and slowly creeps all the way back to the stem. ALL of the leaves are doing this. There are no holes in the leaves. The plant is indoors in a large planter that is allowed to drain and sits adjacent to a window with blinds that are normally closed, allowing only indirect light in. It continues to grow new leaves and occasionally even flowers. I only water it when the leaves begin to droop slightly. Help? (Frisco, TX)
Your plant can maintain only a limited amount of leaves in this type of light. The larger the plant tries to grow, the more of the older leaves that will turn brown and fall off. Also, by allowing the plant to wilt slightly, the soil may have a high concentration of soluble salts from the water and from old fertilizer that should be leached out from time to time. Take the plant outdoors in a shady location, water it thoroughly until the water comes out of the bottom, and repeat this for a couple of more times. Once it drains you can move it back into its location. Keep the old, brown leaves removed to keep it as clean as possible and try to provide as much light as you can. The more light that you give your plant, the more leaves that it will produce.