If your pothos leaves are turning yellow, it might be helpful to first identify what is the variety of pothos in question—it may have naturally yellow leaves! In fact, the variety Golden Pothos has yellow and green variegated leaves, and Neon offers a chartreuse hue. Regardless of the variety, it is typical for older leaves to turn yellow and drop off. Then most of the healthy leaves are left at the end of the vine. To maintain a healthy plant and promote new growth, cut it back 2 inches from the soil line. Besides natural aging, leaves on a pothos can turn yellow for several easy-to-fix reasons: too much direct sunlight; too much or low-quality fertilizer; or exposure to cold or hot temperatures. Fortunately, even if your pothos plant has yellowing leaves, you can likely renew its health by identifying the problem and fixing it effectively.
Causes of Yellow Pothos Leaves
Here are five specific problems that may be causing pothos leaves to turn yellow:
Root Rot (Pythium Root Rot)
When pothos has pythium root rot, the roots look black and mushy; mature leaves yellow and fall off the plant. (With bacterial leaf spot disease, water spots will appear with yellow halos on the leaf undersides.) Root rot is caused by overly saturated soil, which can be a result of overwatering, poor drainage, or heavy soils.
Bacterial Wilt Disease
Bacterial wilt disease happens most often when infected cuttings do not root as they are meant to. Bacterial wilt then sets in. Veins and stems blacken, and the bacteria—Ralstonia solanacearum—may seep into the water the cuttings are sitting in. This pathogen can destroy further propagation of the plant.
Southern Blight
Southern blight is called such because it’s more apt to happen in southern climates because of warm weather conditions. Symptoms of bacterial wilt and southern blight diseases can escalate severely and rapidly during the warm times of the year. Southern blight is caused by the fungus Sclerotium rolfsii, which grows especially fast in wet soils and hot temperatures. The first sign of southern blight happens when lower leaves discolor and wilt. White, fungal threads may grow on both stems and in the soil. This fungus then produces pectolytic and cellulolytic enzymes, plus oxalic acid. All will cause the plant’s cell walls to waste away.
Manganese Toxicity
Manganese toxicity is another problem to keep an eye out for. While bacterial wilt and southern blight can occur in younger plants, excess amounts of the element manganese are more readily a problem in older pothos plants. Such excess may cause the plant to look diseased, but manganese toxicity is caused by too much manganese in the soil. Manganese toxicity is most commonly noticed in nursery plants that absorb too much manganese from the commercial fertilizers they’ve been fed with.
Ethylene Damage
Ethylene damage also presents like a disease, but it is not. It’s caused by certain fungicides that may cause leaves to turn yellow and beige. Ethylene damage in particular usually occurs in cooler weather, like fall and winter. Like manganese toxicity, Ethylene damage is also not actually a disease. Ethylene is a natural gas. It arises from deteriorating plant matter and sometimes by malfunctioning greenhouse heaters that warm the plants but don’t provide good airflow.
How to Treat Yellowing Leaves on Pothos
If your pothos has root rot, you’ll need to first take care of the diseased roots. Disinfect a pair of scissors with a mixture that is 1 part bleach and 9 parts water, then snip off the yellowing leaves. To create the cleanest of conditions, disinfect the scissor blades after each cut. Dig up the plant and cut off all the roots that are mushy and brown. Clean the pot, rinse off the roots with water, and return the plant to the pot with fresh potting soil. Be sure it is placed where it gets part sun to part shade, that the soil is draining, and that it is not overwatered. Avoid misting the plant because the fungi that cause root rot prefer moisture. To treat bacterial wilt on a small scale, for a single plant, try cutting a diseased stem near the soil level, placing the cut stem in a clear vase, and letting the milky substances run out of the infected plant. If an outbreak occurs, have all the plants, pots, and soil bagged and taken away from the location. Disinfect surfaces and garden tools, Similarly with southern blight, be sure to discard both infected plants and their pots. Treat healthy plants with a fungicide solution that has pentachloronitrobenze (PCNB) or flutolanil as active ingredients. To treat manganese toxicity, stop using any fertilizer with manganese as an ingredient (the list of ingredients will say maneb or mancozeb), and avoid those with trace elements as well. Adding lime to the soil helps your plants get healthier. To treat Ethylene damage, make sure greenhouse heaters have good air supply and are in good working order before the winter.
Prevention
Both southern blight and Ethylene damage can be prevented. To avoid another bout of Southern blight in your pothos, keep potting mixes off the ground where Sclerotium could contaminate it. To prevent further Ethylene damage, avoid shipping or mixing flowers, other foliage, or vegetable plants with pothos, which could infect it yet again with a range of diseases, pests, and other issues. Root rot can also be prevented by increasing drainage and adjusting your watering schedule. Regardless of what you do, a certain amount of yellow leaves can be expected because it happens naturally when plants age. It’s just a part of the leaf life cycle.
