Keep philodendron soil moist; it should be watered when the soil surface starts to dry out. Never allow it to get waterlogged or to dry out completely. Philodendrons with dry soil suffer from leaf damage and leaf loss.
Excess fertilizer salts in philodendron soil cause their leaf tips to turn downward and their leaf margins and tips to brown. Flush out the philodendron's soil with water if it develops brown leaf tips or if a white deposit forms on the surface of the soil. Fertilize philodendrons every two weeks during the summer with a liquid houseplant fertilizer diluted by 50 percent.
Philodendrons exposed to cold temperatures develop brown patches on the leaves. Keep your philodendron at a temperature range of between 70 to 85 degrees F during the day and 65 to 75 F at night. To prevent leaf damage, never let the temperature drop below 60 F.
A lack of potassium causes mature philodendron leaves to develop brown leaf margins that expand toward the center of the leaf. Treat it by feeding with a high potassium fertilizer.
Philodendron tips develop brown patches on their leaves and brown leaf tips if they are exposed to direct sunshine. Move your plant out of the sun if its leaves are being damaged. If your philodendron develops bronzed leaf margins, it is receiving too much light. Move it further away from the window.