Pepper plants are popular as peppers are used in many food preparations. They belong to the genus Capsicum, of the Piperaceae family of flowering plants. Common types include green and red bell peppers which are used as vegetables, hot peppers such as tabasco, and other types used as ornamental plants. Pepper plants can also turn yellow for reasons such as lack of or excessive moisture in the soil. Read on for some insightful details on why pepper plants may turn yellow.
Pepper Plants Turning Yellow: What Are The Reasons?
1. Water stress
Pepper plants tend to suffer from yellow leaves, low production and stunted growth due to watering inconsistencies. Overwatering can cause yellowing, but the effect is the same if the plants are underwatered. Watering too little or too much could lead to stress in pepper plants. You need to get the balance right and water just enough so that the soil stays moist, but not wet.
Pepper plants in planters or containers need plenty of drainage holes to avoid waterlogged roots. They cannot access enough oxygen without proper drainage, and this could lead to yellowing leaves, smaller fruits and productivity issues. These plants can more easily handle being dried out than being overwatered, so you should ideally stick to the dry side.
How to fix the problem:
Check the soil moisture of your pepper plants daily by sticking your finger into the soil. If it is moist around two inches down, they do not need to be watered. If the soil is dry, you should water the plants. You can also use a water meter to measure the water and the pH level in the soil.
2. Nitrogen deficiency
Yellowing leaves on pepper plants can be a sign of nitrogen deficiency. Without nitrogen, plants are unable to grow strong, healthy and have green leaves.
The yellowing starts at the bottom of the plant and will slowly move upward. This is because nitrogen is a mobile nutrient and can move from one part of the plant to another. Plants tend to move the remaining nutrients into newer leaves from the older ones when there is a nitrogen deficiency. The older leaves turn yellow first and then fall off.
Aside from yellowing leaves, pepper plants with a nitrogen deficiency will have stunted growth and the leaves and flowers will fall off.
How to fix the problem:
Fertilizing the plants is the best way to resolve this problem. Feed the plants with fertilizer at least once weekly throughout the growing season. The fertilizer should provide enough nitrogen to keep your plants from developing yellow leaves.
3. Other nutrient deficiencies
Your pepper plants may also be deficient in other nutrients such as magnesium and calcium. These nutrients are also necessary for plant growth, and a lack thereof can also lead to yellow leaves.
You will know your plant is magnesium-deficient if the yellowing starts at the bottom of the plant but, unlike in nitrogen-deficient plants, the leaves’ veins remain green but the flesh turns yellow. This process is called chlorosis, and is the quickest way to differentiate magnesium deficiency from nitrogen deficiency.
Calcium is vital in the development of strong cellular walls and without it, the plants will struggle to absorb the required nutrients and will have trouble bearing fruit. This nutrient is also essential in the expansion of the root system. Calcium-deficient plants will have curled leaves with brown spots, as well as yellowing leaves.
How to fix the problem:
Epsom salts increase the magnesium in the soil and crushed eggshells should also be added to provide magnesium and calcium. Enrich the soil with compost, especially before the next growing season to avoid having nutrient-deficient plants.
4. Disease
Yellow leaves on pepper plants could also be due to bacterial leaf spots, phytophthora blight or wilt. Aside from yellowing leaves, you will also notice that the plants will have black lesions on the leaves, brown leaf spots and become wilted.
How to fix the problem:
Most diseases that cause yellowing leaves on pepper plants are untreatable. You may have to discard your plants or, if the damage is not yet too widespread, separate and quarantine them so they have time to heal and become normal again.
5. Pest infestation
Pests can cause damage to pepper plants, including yellowing leaves. They include spider mites, aphids, flea beetles and whiteflies. They suck on the sap of plants and weaken them, which could lead to disease or death.
If you take a closer look at the yellowing plants, you will notice that there are tiny dot patterns on the top and underside of leaves due to the pests. Aphids and whiteflies are often found on the bottom of the leaves.
How to fix the problem:
Pesticides eradicate pests effectively but they are toxic and unhealthy for humans and animals. Organic options include neem oil, which only kills harmful insects. Isopropyl rubbing alcohol or liquid dish soap and water are also good options.
Conclusion
Pepper plants are common food ingredients that add flavor and aroma. During the growing season, they tend to turn yellow due to lack of or excessive water in the soil. Aside from water stress, yellowing of pepper plants may also be attributed to nutrient deficiency, disease, or pest infestation.
Image: istockphoto.com / Tatiana Mironenko