watering your philodendron too much can cause leaves to curl and turn yellow. overwatering is the number one cause of leaf curling in philodendrons. if you notice that your philodendron's leaves are curled or turning yellow, it's time to water less often. here's how to fix it: first, check the soil moisture level. if it's below the surface of the potting mix, water deeper and allow excess water to drain away for several hours before watering again. If soil moisture is above the surface of the potting mix, water sparingly and only when necessary. Make sure that your philodendron is receiving at least 12 hours of sunlight per day, direct sunlight will help promote healthy growth.