Why are my Pepper Plant Leaves Turning Yellow?

Yellowing or premature browning, instead of bright green leaves, may indicate a pepper plant is under duress.

Remember, yellowing may occur any time of the year, but leaf yellowing in spring and summer may indicate a grave problem.

Is It Normal for Pepper Leaves to Turn Yellow?

If you have started peppers from seed or transplanted a young sapling, you probably have encountered yellow leaves at some point.

Do not worry yet because some yellowing is natural with pepper leaves that are aging and dying.

You would usually witness some leaf yellowing and dropping in fall and winter when the plant becomes dormant.

However, witnessing yellowing foliage in spring and summer may be unusual because the plant thrives in the growing season.

Why are my Pepper Leaves Turning Yellow? (Causes & Solutions)

First, you need to know if pepper is fruit or vegetable. 

If your pepper plants turn yellow in leaves, know the immediate causes or incomplete care requirements. 

1. Watering Stress

Both overwatering and underwatering will harm pepper plants.

Overwatering the plant will drown the roots, leading to low oxygen and nutrient intake.

Moreover, excessively wet roots may also lead to bacterial infection, affecting the plant’s metabolism and chlorophyll production.

Similarly, inconsistent and low watering will compact soil, leading to choked roots.

Remember, most pepper species are not drought-tolerant plants, except hot peppers containing moisture.

In both cases, the plant leaves will turn bright yellow or yellowish, significantly lower leaves.

2. Nitrogen Deficiency

Pepper would need a regular nitrogen supply early in the growing season to produce greener growth and support later fruiting.

When deprived of nitrogen, the pepper leaves will begin yellowing, starting at the bottom and gradually moving upwards.

Therefore, the older and bottom leaves are the first ones to experience nitrogen insufficiency.

Check out for vivid pale yellow and wilted leaves at the bottom of the plant while the top is still looking healthy.

Some other telltale signs include stunted plant growth, wilted flower buds, and leaf drop.

Immediate Actions to Take

• Use a pH scale meter to check if the soil measures anything between 6.0-7.0.
• Then, amend the soil with lime (calcium carbonate) to raise the pH or elemental sulfur or sulfates (iron or aluminum) to lower the pH.
• Consider amending the soil with compost, garden soil, or sand with less carbon content.
• If you have missed out on fertilizing, consider redoing it with a proper formula.
• Use fertilizer with NPK 5-5-5 or NPK 6-5-5 and apply every two weeks until the plant revives.

3. Cold Stress

Peppers are warmth-loving plants that will only have blossoms and bear fruit in temperatures above 60°F.

When the plant undergoes cold temperatures, especially an outdoor-grown plant, you will begin seeing yellow leaves.

Temperature as low as 50°F (10°C) would wilt the leaves and change their color as the plant enters hibernation as a natural response.

The plant may even die if the temperature begins dropping below 40°F.

Immediate Actions to Take

• Move the potted plant from the windows and patio indoors.
• Move the plant under LED grow light, especially when the temperature drops.

• Alternatively, you can use a heat mat or cover the plant using a plastic specially designed to regulate heat around the plant.
• It may be best to avoid fertilizing the plant when it is under severe cold stress.

Note! The temperature above 90°F can be equally detrimental to the pepper plant, requiring the transfering the plant to a cooler and shaded location.

4. Micronutrient Deficiency

A lack of a variety of micronutrients, primarily magnesium and calcium, may cause pepper leaves to turn yellow and later brownish.

Magnesium deficiency, in particular, will cause leaves to turn yellow at the bottom, similar to nitrogen deficiency, but the veins remain greener.

Leaf margins of older leaves will turn yellow, leaving the veins green while leaving white to light brown necrotic dots.

On the other hand, calcium deficiency will weaken your plants’ cellular walls, leading to troubled fruiting and root expansion, where you may witness curled leaves, yellowing, and brownish spots.

Immediate Actions to Take

• The only solution to fix magnesium and calcium deficiency in pepper plants is introducing the micronutrients into the soil.
• Start adding Plant Supplement sprays to give a micronutrient boost to the plant roots as a short-term solution.
• Amend the soil with 100% Epsom salt to promote healthier magnesium uptake from fertilizers.
• Along with regular fertilization, introduce crushed eggshells, carb shells, and fish meal to gradually supply missing micronutrients.

5. Chlorine Toxicity

Chlorine residue in the soil can lead to salt toxicity, affecting the soil’s healthy bacteria and microorganisms.

Similarly, high chlorine levels can damage the root and affect its ability to retain oxygen and nutrients.

So, gardeners advise avoiding tap water and mineral water for watering pepper plants.

Immediate Actions to Take

• Start dechlorinating the soil by running it under fresh water.
• As a preventive measure, leave the tap water in the sun to naturally remove chlorine or use dechlorination tablets.
• Otherwise, use only rainwater to water the plant.

6. Pest Infestation 

A pest infestation, particularly mites, aphids, psyllids, white flies, and flea beetles, may cause yellowed pepper leaves.

Although pest infestation will not kill your pepper plant, it will do enough damage that it may seem impossible to revert.

So, the immediate solution is to remove pests, pest eggs, and droppings or residue. 

Immediate Actions to Take

• Trim heavily affected parts and remove visible pests.
• Wash your pepper plant with mild soapy water or horticultural oil to remove pests and their eggs effectively.
• Rub insecticidal soap or neem oil on the infected parts will also help remove and prevent infestation.
• Use chemical pesticides like Pyrething or imidacloprid if the infestation seems to be present even after initial treatment.

If you hunt to learn treating pest infestation in detail, you need to identify insect eggs on leaves. 

7. Horticultural Diseases

The pepper plant is particularly prone to fungus and bacterial infestations like phytophthora blight, bacterial leaf spot, Southern blight, and fusarium wilt.

You would mostly witness discolored leaves with pale green or yellowish texture, but the symptoms may vary.

Immediate Actions to Take

• Trim the infected parts with sterilized pruning shear and dispose of the infected parts carefully.
• Do not forget to rub the neem oil on both top and undersides of the leaves.
• Alternatively, apply liquid copper fungicide twice in the growing season to remove the fungus.

Should I Cut the Yellow Leaves Off the Pepper Plant?

Cutting off old, decayed, and yellowed leaves will prevent the plant from sending energy toward recovering the dying foliage.

So start cutting off old and yellow leaves, diseased stems, spent flowers, and unappealing yields.

• Cut down the entire bush to 1/3 of the plant covered with yellow leaves.
• Prune off all of the pepper growing points about 3-4 weeks before the arrival of the first expected frost.
• Prune off the top 3-6 inches of every branch and side shoots to boost new growth.
• Avoid cutting back the pepper plant until it has reached a height of at least a foot (31 cm).

Get some information regarding pruning from the video below!

How to Prevent Pepper Leaves from Turning Yellow?

Start with a well-draining potting soil mix of vermiculite, perlite, peat moss, and sand mixed with lots of organic matter like compost.

• Provide potted pepper with 6-12 hours of direct sunlight in spring and summer in the east or south-facing direction.
• Install room humidifiers to maintain moderate humidity (around 50-60%).
• Try maintaining temperatures between 70-90°F during the day and a minimum of 60-70°F at night.
• Use balanced fertilizer rich in micronutrients like calcium and magnesium and apply biweekly or once a month in spring and summer.
• Water the peppers daily during summer and hydrate the plant once every 2-3 days during spring and fall.