The Pothos (Epipremnum aureum) is celebrated for its trailing growth and forgiving nature. Brown leaves are the most frequent sign of distress, indicating that plant tissue is dying. This often results from an inability to manage water, nutrients, or light effectively.
Water Stress: The Primary Culprit
The most common reason for tissue death in Pothos is an imbalance in water intake, which manifests in two distinct ways. Under-watering causes the plant to conserve moisture by sacrificing leaf tissue, resulting in light-brown, dry, and crispy edges or tips. This occurs because the plant loses turgor pressure and cannot transport water adequately to the leaf extremities, causing dehydration.
When the soil becomes too dry, the water-conducting structures in the plant shut down to minimize moisture loss, leading to the characteristic crisp texture of the brown areas. A deep, thorough soaking until water drains from the pot is the necessary fix, allowing the roots to rehydrate fully.
Conversely, over-watering leads to dark, mushy, black-brown spots, often near the base of the leaf or stem. This softer browning is a sign of root rot, where prolonged saturated soil suffocates the roots by cutting off oxygen supply. Without oxygen, anaerobic pathogens begin to consume the root tissue. Damaged roots cannot absorb water, paradoxically causing the leaves to wilt and brown despite the wet soil. Treatment involves allowing the soil to dry completely, checking the roots for black or slimy sections, and repotting the plant into fresh, well-draining soil.
Light and Air Quality Problems
Browning can also result from environmental factors unrelated to soil moisture. Placing a Pothos in direct, intense sunlight can lead to sunburn, which appears as large, irregular, bleached, or scorched patches on the leaf surface. This light exposure overwhelms the leaf’s chlorophyll, causing localized cell death and resulting in permanent, crispy brown or white spots. The solution is to move the plant to a location that receives bright, indirect light, a condition Pothos naturally prefers.
Air quality, specifically low humidity, can also cause browning, even when the soil is kept appropriately moist. Pothos originates from tropical climates and requires humidity levels above 50% to thrive. In dry indoor environments, water loss through transpiration occurs too quickly, leading to the browning and crisping of leaf edges and tips. This symptom is similar to under-watering, but the surrounding air, not the soil, is the source of the problem. Increasing ambient moisture with a humidifier or a pebble tray filled with water can help reduce this localized desiccation.
Soil Health and Mineral Buildup
The chemical composition of the soil and water can also contribute to leaf browning through the accumulation of excess soluble salts. Fertilizer burn occurs when excessive amounts of plant food are applied, causing the concentration of salts in the soil to rise dramatically. This high salt concentration reverses the osmotic pressure gradient, drawing moisture out of the roots and dehydrating the plant tissue. Symptoms include brown, scorched leaf tips and margins, and sometimes a white crust forming on the soil surface.
A similar issue arises from mineral accumulation found in hard tap water, which contains chlorine and high levels of dissolved salts that build up over time. This mineral buildup can also burn the delicate root hairs and leaf tips. To correct both fertilizer burn and mineral accumulation, the soil must be “flushed.” This process involves slowly pouring a large volume of clean, filtered, or distilled water through the pot multiple times, allowing the water to drain completely to wash away the excess salts from the substrate.