Pepper plants, Capsicum sp., can be a difficult yet rewarding species to cultivate. They require long growing periods and specific conditions to produce fruit; and, if those conditions are wrong, then it can create issues that lead to bad pepper production. A common affliction of pepper plants is yellowing leaves, which can be caused by a multitude of complex problems.
Fortunately, the solutions exist and are easy to implement. You must find the culprit, implement the solution, and wait for delicious peppers! This article will help you stop pepper plant leaves turning yellow, or guide you on how to fix any yellowing already taking hold.
Why Does My Pepper Plant Have Yellow Leaves?
Yellowing leaves are an important first sign that there is a problem with your pepper plants. The discoloration is called chlorosis and it occurs when certain environmental factors cause the plant to produce insufficient amounts of chlorophyll.
Because chlorophyll is what makes plants green, they appear pale or yellow after chlorosis occurs. The most common environmental factors that can cause a pepper plant’s leaves to turn yellow include nutrient deficiencies, inadequate watering schedules, low temperatures, disease, and pests.
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Nutrient Deficiencies
Nutrient deficiencies are the lack of macro and micronutrients in the soil that are needed for plants to complete their metabolic activities related to growth and reproduction. All plants require 14 different mineral components to grow and when these nutrients, such as nitrogen, magnesium, and iron, are in short supply it can cause issues such as stunted growth, poor fruit production, and discoloration of foliage.
Necessary nutrients such as nitrogen and potassium are the most common culprits of yellowing leaves but can also be caused by a lack of sulfur, magnesium, calcium, and zinc. These deficiencies can be treated with a properly applied fertilizer regimen. For the health and safety of people and the environment, follow all guidelines set forth by the manufacturer.
Nitrogen Deficiencies in Pepper Plants
Deficiencies in nitrogen are common in pepper plants. Symptoms include yellowing of leaves occurring in older and lower leaves first and progressing to younger leaves as the deficiency worsens. This is often caused by a lack of organic matter in the soil, nutrient leaching after heavy rain or overwatering, or inadequate fertilization schedules. Nitrogen deficiency is more likely to occur during the later stages of growth when its uptake needs to increase.
Mulching is beneficial by retaining soil moisture and repelling heat but using a layer of wood chips will steal nitrogen from the pepper plants as it decomposes. Add a nitrogen-rich fertilizer to the soil if you choose to use wood chips. Also beware of any mulch like grass or straw that may contain weed seeds or moldy material, which could attract pests to your garden.
Lack of Potassium
Potassium deficiencies in pepper plants will show signs of yellowing along the edges and veins of the leaves. The leaves will also exhibit curling. Symptoms will begin in the older leaves and progress to younger leaves as the deficiency becomes more severe.
Chlorosis symptoms will usually begin to show by mid-summer and will continue to a grey color as the deficiency worsens. Potassium becomes less bioavailable during times of drought.
Lack of Sulfur
Sulfur deficiencies are often misdiagnosed as nitrogen deficiencies due to their similar symptoms, but a lack of sulfur will present with interveinal yellowing as well. The chlorosis also starts out more pronounced in the upper, younger leaves of the plant compared to that nitrogen deficiencies.
Lack of Magnesium
Magnesium is an essential component of chlorophyll and photosynthesis and deficiencies major discoloration of pepper plant leaves. Magnesium deficiencies will initially appear as yellow interveinal stripes in the lowest shoots but will quickly progress to include yellowish-brown round spots and reddish-purple tips throughout the entire pepper plant.
Lack of Calcium
Calcium deficiencies are common in pepper plants, especially in the bell pepper varieties. The beginning symptoms of calcium deficiency include yellowing of leaves and stunted growth. If the deficiency continues it will create major fruiting problems, including rotten flesh in the ripening peppers.
Calcium deficiencies can ruin entire crops of peppers but are easily prevented by maintaining an adequate fertilizer schedule. Calcium becomes less bioavailable during times of drought.
Lack of Zinc
Zinc is an important micronutrient that is usually tested to be the third most common deficiency in growing plants. Zinc is used in the production of chloroplasts which is why the deficiency symptoms begin with interveinal yellowing leaves, but as it progresses the color bleaches and the discoloration becomes predominantly white.
Pepper Plants Turning Yellow Even with Fertilizer
If your pepper plants’ leaves are persistently turning yellow like symptoms of a nutrient deficiency yet you have applied a fertilizer, then there may be an alternate problem affecting the ability of your plants to uptake nutrients. Nutrient availability can be influenced by many factors including soil type, pH, and soil moisture. Adding organic matter to the soil before planting will help increase the number of nutrients available for plants to uptake, along with increasing the aeration and overall quality of the soil.
PH levels can interfere with the capability of plants to absorb nutrients by rendering available nutrients useless. Soil with a high amount of organic matter can buffer pH changes better than soil that is sand or silty clay.
Maintaining an adequate moisture level in the soil from consistent watering will supply the plant’s roots with the necessary water it needs to transport nutrients. If a plant’s soil is too dry, then the plant’s roots can begin to dry, and nutrients will begin to go deficient.
Nutrient Toxicity
Plants require those necessary nutrients, but if they are in too high of concentrations, then it can cause nutrient toxicity, which could present symptoms including chlorosis. The easiest way to determine the exact level of nutrients in the soil is to use a handheld nutrient level meter, which can be purchased at any local growing supply store.
Salt Toxicity
Salt toxicity symptoms present like potassium deficiency with severely yellowing leaves but are caused by an excess of sodium. Pepper plants can survive low concentrations of salt by flushing the soil with fresh water, but high concentrations will kill most vegetative species.
Over or Under Watering
Creating and executing a proper watering schedule can be tricky for pepper plants. It is best to water your pepper plants during the morning or evening hours so that any water left on the leaves has a chance to evaporate before the hottest part of the day, which prevents it from heating up and causing damage to the surface of the leaf. This can easily be achieved by using ground watering techniques like a soaker hose.
Test the moisture level of the soil by sticking your finger at least 2 inches into the soil near the plant. It should have a consistent moisture level throughout. No dry spots or standing water should be allowed to remain in the soil of the garden area.
Over Watering
While pepper plants need moist soil, overwatering is one of the biggest mistakes you can make with your pepper plants. Saturated soils will quickly deplete oxygen, and pepper plants are very intolerant to those conditions.
The extreme stress from remaining in these conditions will quickly cause the pepper plant to die. This can be prevented by using mounds of soil around the pepper plant to direct standing water away from the stem and roots. Evidence of over-watering can include yellowing of leaves, wilting, and severely stunted growth.
Under Watering
Pepper plants require daily watering during the hot summer months and often need to be watered twice a day during times of extreme heat. Using a soaker hose can limit the guesswork, as it pulls water into the soil as it becomes dry, but the soil moisture will still need to be checked often.
Without enough moisture level in the soil from consistent watering, plants’ roots can begin to dry out and die, and nutrients will begin to go deficient. Evidence of under-watering can include yellowing of leaves, severe wilting, and dry texture to leaves and soil.
Low Temperatures
Low temperatures can cause your pepper plant leaves to turn yellow. Pepper plants originate from tropical climates, and they would prefer the temperature to be above 60 degrees Fahrenheit during the entire season.
Some especially sensitive pepper varieties are known to start dropping their leaves below 40 degrees Fahrenheit. Any amount of frost will kill your pepper plants, but the fruit can still be harvested after a freeze event.
Pests & Diseases
Pepper plants can be a host to many pests and diseases, including spider mites, bacteria, and leaf curl viruses. Be particularly watchful during the seedling stage as this is when the pepper plants have the least likelihood of recovery after a major attack.
Integrated Pest Management (IPM) is a scientifically proven way to control these unwanted insects without using excessive insecticides. It includes removing invasive plant species, planting native species, creating shelter to attract predatory insects and birds, and companion planting techniques.
Spider Mites
These tiny insects can do big damage if left unmanaged. Spider mites will leave small yellow dots all over the surface of the leaves, along with webbing present on the undersides of the leaves. They are very hard to completely get rid of, especially outdoors, but the populations can be easily managed by washing the leaves with mite-specific insecticidal soap, or a mixture that includes essential oils such as lemongrass and neem.
Other Insects
Aphids, white flies, beetles, and borers can all be attracted to pepper plants. All cases of damage from insects will include evidence of actual leaf damage from the infestation along with the presence of yellowing or browning leaves.
Pepper Yellow Leaf Curl Virus (PYLCV)
This virus from the Polerovirus genus includes symptoms of interveinal yellowing of leaves, accompanied by the disruption of growth of the stems and fruit, and the upwards rolling of the leaf edges. These cases are usually fatal to the plant and all infected plants should be removed.
Verdict: Pepper Plant Leaves Turning Yellow
Yellowing leaves, or chlorosis, is a common affliction of pepper plants and can be caused by a multitude of problems, including nutrient deficiencies, inadequate watering schedules, low temperatures, soil issues, disease, and pests.
- Nutrient deficiencies like nitrogen, potassium, sulfur, magnesium, calcium, and iron, can cause issues such as stunted growth, poor fruit production, and discoloration of foliage. These deficiencies are commonly treated with a properly applied fertilizer regimen.
- Nutrient availability can be influenced by many factors including soil type, pH, and soil moisture. Adding organic matter to the soil before planting will help alleviate these issues.
- Pepper plants require daily watering during the hot summer months and twice a day during times of extreme heat. Without suitable moisture levels in the soil from a consistent watering schedule, roots will begin to dry, and nutrients will begin to go deficient.
- While pepper plants need plenty of soil moisture, overwatering is one of the biggest mistakes you can make with your pepper plants. Saturated soils will quickly deplete oxygen, and pepper plants will quickly die under those conditions.
- Pepper plants can be a host to spider mites, bacteria, and leaf curl viruses, among many others. Integrated Pest Management is a scientifically proven way to control these unwanted insects without using excessive insecticides.
