Yellow leaves on pepper plants are not merely unattractive, they indicate that the plant has a serious problem. Chilies and sweet peppers are both popular among home gardeners because they can thrive in many different conditions; however, their toughness doesn’t mean that they are invulnerable. Pepper plants turning yellow signals a problem in the plant’s environment or its health.
When leaves turn yellow, the plant may have a disease. Or it may be undergoing a pest attack. Or it may be lacking something it needs. Yellow leaves won’t ever become green again, but you may be able to correct the problem and return the pepper plant to good health. Below is a look at some of the factors that can result in the leaves on pepper plants turning yellow.
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Underwatering or overwatering
Too much or too little water will each cause the same kinds of symptoms in pepper plants, including yellow leaves. Pepper plants can only tolerate water within a specific range. Too little water will cause the plant to wilt in addition to turning the leaves yellow. The amount of water that you are giving the plant is not always the problem. If the soil around the plant has become compacted, it may keep water from getting to the roots and being absorbed, which results in the same symptoms as underwatering.
Consider repotting a plant in a container. Relieve compacted soil in a garden by punching holes with a garden fork or adding compost.
Overwatering is an especially common problem with pepper seedlings but can affect plants at any age. Even if your pepper plants are getting the right amount of water, they might still show signs of overwatering if you don’t provide them with adequate drainage. Both the soil and the containers for pepper plants should allow water to flow out. The roots of plants in waterlogged soil will start to rot and the excess water may wash nutrients from it, which results in leaf-yellowing. Make sure to plant your pepper plants in soil that drains well and choose a container with holes that are large enough.
Another tip to ensure that pepper plants don’t get too much water is to let the soil dry out a little before you give them more water. The surface of the soil in the container or around a plant in the ground should be dry to the touch when you water pepper plants.
Certain diseases can cause pepper plant leaves to turn yellow. Diseases that can do this include phytophthora blight and bacterial leaf spot. Southern blight and fusarium wilt will also cause leaf-yellowing. Avoiding extremes of wetness and dryness is the best way to prevent all four diseases.
Diseases that affect pepper plants are often untreatable. If they cannot be treated, you will need to remove the diseased pepper plants from your garden. It is also recommended that you wait a year before planting more nightshades in the same location, or they might be infected with the same disease. Your pepper plants may be more susceptible if you live in a damp tropical climate.
The most effective way to manage bacterial leaf spot is to prevent the disease in the first place. Try to avoid getting your pepper plant leaves wet too often. Focus your watering on the base of the plant rather than on the leaves.
Some pests can cause your pepper plant leaves to turn yellow. Mites and aphids consume the plant’s water and nutrients, which may cause the leaf yellowing. If you believe that insects are attacking your plants, your options include treating them with a pesticide.
Ideally, you want an organic one that will kill the pests without harming beneficial insects or people. Your options include neem oil, which suffocates pests or disrupts their ability to feed. Insecticidal soap is another safe product that works by washing away the coating on the outside of the insect’s body, which kills them.
Leaf yellowing caused by insects is only likely to occur if your plants are heavily infested, so it will usually be pretty clear if insects are the cause.
If your plant is deficient in some important nutrients, this could result in the leaves turning yellow. Nutrient deficiency may be the most common reason for yellow leaves. If you notice that the leaves on the plant are turning yellow starting at the plant’s base and the yellowing is moving upward, the cause is most likely missing nutrients.
One of the nutrients responsible for a plant’s growth and healthy green foliage is nitrogen. A nitrogen-deficient pepper plant may show it with yellow leaves. Nitrogen isn’t the only nutrient that keeps the leaves green. If your plant lacks adequate magnesium or calcium, the leaves may turn yellow. In the case of a magnesium deficiency, the leaves may turn yellow except for the veins.
The solution for nutrient deficiencies is to provide the lacking minerals in the form of a balanced fertilizer. Alternatively, you can enrich the soil with magnesium specifically by adding Epsom salt to it, and you can add eggshells to increase calcium.
Magnesium is a key element in chlorophyll, the compound that makes leaves green. Magnesium is also important for photosynthesis, the process by which plants get energy from the sun. Iron is another important mineral that might cause yellow leaves if the plant isn’t getting enough of it. As with a magnesium deficiency, you may notice that the veins in the leaves stay green as the rest of it yellows.
Low temperatures are also believed to cause pepper plant leaves to yellow, though there is not much research about the process by which this occurs. It is well-known that pepper plants do not like temperatures below 60 degrees Fahrenheit, and that plants can start losing leaves at around 40 degrees. Anything under 30 degrees can kill them. If the yellow leaves are distributed all over the plant, the cause of yellowing is most likely low temperatures.
In temperatures below 60 degrees, consider covering pepper plants at night to help them stay warm. Keeping them warm may help to keep leaves from yellowing, even if temperatures never approach freezing.
Too much chlorine
If there is too much chlorine in the soil, pepper plant leaves can turn yellow. The chlorine may come from water, or it may be the residue from fertilizer given to plants over the years. Yellowing because of excessive chlorine is rare, so you may want to investigate the other causes on this list first.
If too much chlorine is causing the yellow leaves, you can try washing out the chlorine salts from the soil by using only chlorine-free water. You can get chlorine-free water by collecting rainwater or letting tap water sit for a few days until it dechlorinates.