The most common reason for pothos leaves curling downwards, and inward is underwatering. When the plant is thirsty, it will try to reduce water loss through transpiration by decreasing the surface area of its leaves. In simple terms, the plant will start curling its leaves.
Root rot and overwatering go hand in hand. If the soil in the pot is waterlogged or has poor drainage, it can harbor pathogens like Rhizoctonia and Phytophthora, which will kill your plant’s roots.
Pothos can tolerate humidity levels as low as 40%. But if the air in your home is too dry, its leaves will start curling inwards in an attempt to preserve moisture.
During the colder months, indoor heating can increase the temperature around the plant while also lowering humidity. If your pothos is sitting too close to a radiator or heating vent, hot drafts can cause the leaves to curl.