The Pothos plant (Epipremnum aureum) is a highly favored houseplant, often chosen for its ease of care. Many people choose to propagate or grow this trailing vine in a simple container of water, a method that successfully promotes root development. However, after an initial period of healthy growth, you may observe the leaves beginning to yellow, a condition known as chlorosis, which signals that the plant is under stress. This article will diagnose the underlying issues that cause yellowing leaves and provide advice to correct the problem.
The Core Cause: Depleted Nutrients in Water
The primary reason a Pothos cutting begins to yellow after successfully rooting in water is the absence of sufficient nutrients in its environment. While water is adequate for hydration and root formation, it is largely devoid of the macro- and micronutrients necessary for long-term vegetative growth. A freshly cut stem initially uses the energy and mineral reserves stored within its tissues to produce new roots and leaves.
Once these initial reserves are exhausted, the plant can no longer synthesize enough chlorophyll, the pigment responsible for the green color and the process of photosynthesis. This lack of chlorophyll manifests as yellowing, or chlorosis, often starting with the older leaves as the plant sacrifices them to redirect limited resources to newer growth. Nitrogen is a significant component of chlorophyll and is often the first element depleted, leading to an overall pale yellowing of the entire leaf.
Other essential elements like Magnesium and Iron are also quickly depleted from the water medium. Magnesium deficiency typically presents as interveinal chlorosis, where the tissue between the leaf veins turns yellow while the veins remain green. Iron deficiency, conversely, tends to affect newer growth first, causing the youngest leaves to emerge pale yellow or white. Plain tap water cannot sustain the mineral demands of a plant trying to grow long-term.
Environmental Stressors Affecting Water-Grown Pothos
Although nutrient deficiency is the most common cause of long-term yellowing, several environmental factors can contribute to chlorosis in water-grown Pothos. Light exposure is a frequent culprit, as the plant requires bright, indirect light to produce sufficient energy. If the location is too dark, the plant shuts down chlorophyll production, leading to yellowing and leaf drop. Conversely, direct, intense sunlight can cause leaf scorch, appearing as bleached or yellow-brown patches.
The quality and oxygenation of the water itself also play a significant role in maintaining root health. Stagnant water quickly becomes depleted of dissolved oxygen, which the roots need for respiration and nutrient uptake. When roots are starved of oxygen, they become stressed and begin to rot, hindering nutrient absorption. Regularly changing the water every one to two weeks ensures a fresh supply of oxygen and prevents the buildup of waste products.
Furthermore, extreme temperature fluctuations can induce stress that results in leaf yellowing. Pothos plants prefer stable indoor temperatures, typically between 65°F and 85°F (18°C and 29°C). Placing a water-grown cutting near a cold window, an air conditioning vent, or a heat source can cause the leaves to turn yellow and wilt. These sudden shifts in temperature shock the plant’s system, disrupting its normal metabolic processes and causing the visible stress of chlorosis.
Recovery and Transitioning to Soil or Hydroponics
Addressing the yellowing requires immediate corrective action followed by a long-term strategy for sustained plant health. Begin by pruning any leaves that have already turned completely yellow, as these leaves will not revert to green and are only draining the plant’s energy. Immediately refresh the water with clean, room-temperature water and move the plant to a location with bright, indirect light to encourage healthy photosynthesis.
For a long-term solution, the most common and successful strategy is transitioning the Pothos from water to a soil medium. When the water roots are at least one to two inches long, gently pot the cutting into a well-draining potting mix containing perlite or orchid bark. For the first few weeks after the transition, keep the soil consistently moist—not soggy—to ease the shock on the water-grown roots, which are accustomed to constant hydration.
Alternatively, if you wish to keep your Pothos permanently in water, you must convert the setup to a true hydroponic system. This requires introducing a specialized liquid hydroponic fertilizer that contains a complete profile of macro- and micronutrients. Using a diluted solution of an all-purpose liquid fertilizer designed for hydroculture, applied with every water change, will provide the necessary mineral balance to prevent future chlorosis and support vigorous, vibrant growth.