Why are my pepper leaves turning yellow?

When your pepper plant leaves turn yellow it is a signal that something is not right or maybe even very wrong. This is when you as a gardener go into detective mode to find out what is causing the yellowing leaves and then proceed to fix the problem.

From my experience, yellowing pepper leaves are usually due to overwatering, compact and waterlogged soil, pests or lack of nutrition.

The good news? If you inspect your plants regularly it is hard to miss leaves turning yellow. And as long as you catch the problem early you should be able to fix the problem and save your pepper plant.

One complicating factor can be that the real culprit to yellowing leaves may not reveal itself at first. Are you overwatering your pepper plants if the soil is wet in a pot that has no drainage holes? 

Here in this article I will list 7 reasons pepper leaves are turning yellow with actionable tips on how to fix each problem.

7 reasons leaves on pepper plants turn yellow

1. Overwatering your pepper plants

Pepper plants take time to germinate, grow and develop fruits. And over time, gardeners get invested in their plants. We want our pepper plants to do well.

And with this desire to take care of our plants, gardeners often water their pepper plants too often and too much. 

The root system needs oxygen as much as it needs water and nutrition. When you overwater your plants you effectively drown your roots and get a condition referred to as root rot. And one of the indications of overwatering is leaves turning yellow on your pepper plants.

Root rot in itself, is easily identified as the roots change color from bright white to dark and brown. The roots also often feel slimy at the touch and there may be some odour.

How to fix problems with overwatering:

First, you need to understand that soil being dry on the surface does not automatically mean that it is time to water your plants. 

You need to accept that a mild dry out is better than roots sitting in constant wet.

If you only have a few pots you can use a moisture meter – or even a wooden stick – to insert into the soil to get an indication of the level of moisture inside your pot.

If you have many potted pants, my best tip is to learn to water by weight. Using a moisture meter is of course great but with more than 100 plants it is not very practical.

Instead, feel the weight of a pot with dry as well as watered soil and feel the difference. After a while, you will be able to feel when it is time to water your plants.

If your plant is suffering from root rot, you may still be able to salvage your plant if you follow the 3 steps below:

  1. Remove all brown, dead roots. Stop when you hit white, healthy looking roots.
  2. Pot up pepper plant into larger pot with new soil that drains well
  3. Place pot in room temperature and avoid direct sunlight for first 1-2 weeks

2. Poor soil resulting in yellowing leaves

Pepper plants need soil with a structure that drains well to grow and develop into healthy plants with lots of fruit to harvest. Yellow leaves are one of the early indicators that your soil is too compact and does not drain well.

Compact soil due to top watering
Compact soil: here in a pot with lemongrass

Soil will also get waterlogged or anaerobic [1] if it retains too much water, gets saturated and thereby leaves less oxygen available in the soil for plants and other important organisms to thrive. Less oxygen will in turn result in root damage, root rot and even plant mortality.

How to fix poor soil

Make sure you use quality potting soil that retains sufficient moisture while still draining well. 

If you mix your own soil, make sure you use amendments like perlite, peat moss, coconut coir and organic compost to create a fertile and well draining growing environment for your pepper plants.

3. Lack of nutrition

Pepper plants need regular feeding to develop and thrive and leaves will turn yellow if your soil lacks in nutrition.

I start feeding my pepper plants after the first transplant into larger pots. I start by giving half the recommended dosage and then increase the dosage as needed. At this early stage I use an all-round (NPK 10-10-10) or nitrogen-based fertiliser to help the plant develop into a strong plant. 

As my pepper plants start to blossom, I move to a phosphorus based (NPK 5-10-5) fertilizer designer to promote the growth of flowers and fruits.

Be careful not to add too much nitrogen to pepper plants in bloom as it can lead to flower drop and less fruits to harvest [2].

How to fix yellow leaves due to lack of nutrition 

Your pepper plants need nitrogen in the early days of development when the plant is developing stems and leaves. 

As the plant starts to flower and develop fruit you should switch to a phosphorus based fertiliser that promotes the development of flowers and fruit.

Always start by giving your plants half the recommended dosage and observe the effects. Remember, it is easy to increase the dosage but very hard to remove already given fertilisers. 

4. Extreme temperatures causing yellow leaves

Pepper plants are tropical plants and prefer a temperature between 15-28 degrees Celsius (60-82 degrees Fahrenheit). And ideally, you can offer an environment with a relatively stable range of temperatures.

Your pepper plants will not do well in temperatures below 10 degrees Celsius (50 degrees Fahrenheit). Also, from experience, we have seen leaves turn yellow when temperatures hit above 30 degrees Celsius (90 degrees Fahrenheit) especially in combination with high levels of humidity.

How to fix yellow leaves due to extreme temperatures: 

Aim for a range of temperature around 20 –   25 degrees Celsius (68 – 77 degrees Fahrenheit) for optimal growth.

5. Pests causing pepper leaves to yellow

Sucking pests that pierce the leaves and feed on the sap of the plant will often discolour the leaves. The result may be yellow, or even brown leaves, that are often curled or misshapen.

For us, aphids are by far the most common pests to attack out pepper plants. Aphids are small and often found underneath the leaves where they sit in groups and feast on your plants.

Aphids underneath leaf making leaf turn yellow
Look carefully and you will see the aphids on this cayenne pepper leaf

Aphids are small 2-4 mm (1/16 to 1/8 inch) long and you may need a magnifying glass to spot them. 

How to fix yellowing leaves and pests: 

Inspect your plants daily and be on the lookout for misshapen, curly, yellow and brown leaves.

Aphids like to sit and feed underneath mature leaves but can also often be found on new growth at the top of the plant. Sometimes, you can find aphids inside a new leaf that is not yet fully open.

When possible, pinch or prune infected leaves and destroy them. We also spray more heavily infected plants with a Neem oil solution

Click to watch our instructional video “How to detect aphids on pepper plants early | Get rid of aphids on pepper plant” or watch below.

6. Wrong size or type of pot can lead to yellowing leaves

Pepper plants grow big and the roots need space to grow and develop. If your pot is too small, leaves will turn yellow as roots are too restricted to absorb water and nutrients.

Another mistake is to choose a pot from a material that does not breathe or that lacks drainage holes.

How to fix

Always use pots with drainage holes or grow bags made from materials that breathe. 

We make DIY grow bags at home as they are ideal for pepper plants and save us quite a lot of money every year.

7. Stress due to wind or other external factors

The yellowing of leaves is not a disease in itself. Rather, it is a signal that something is not quite right.

Besides the factors already listed, leaves on pepper plants can turn yellow from stress.

Typically, external factors have changed and the plant is struggling to cope with the new situation.

Common examples include lack of sunlight, underwatering, exposing plants to wind or forgetting to harden off your pepper plants before they are moved outdoors. 

But it can also be as simple as irregular watering habits or placing a newly transplanted pepper plant in direct sunlight.

How to fix

If the leaves on your pepper plants are turning yellow all of a sudden, always look to recent changes in light, watering, general care, weather conditions and temperature. 

The answer is often right there as long as we take time to think and reflect. 

Summary: leaves on pepper plants turning yellow

Peppers are slow to grow and develop. And as gardeners, we start seeds early and invest time and effort to germinate seeds and develop our young plants.

This is also why most gardeners get so invested in their peppers and tomato plants. We have so many hours invested in each and every plant.

Looking at our pepper plants this season we grow milder and medium hot peppers like Spanish Padron peppers, Jamaican bell peppers, and Cayenne peppers

But we also grow hotter pepper varieties like habaneros and Bhut Jolokia ghost peppers

And for some of our hotter pepper varieties, we need to wait for up to 200 days from seed to full maturity and harvest. 

Given this time you need to invest, remember to pay attention to the yellow leaves on your pepper plants. 

Early detection and taking action can be the difference between a great pepper harvest and a season wasted on caring for struggling pepper plants.

Useful resources:

[1] https://brocku.ca/unesco-chair/2021/02/10/vineyards-and-heavy-rainfall/
[2] https://gardeningsolutions.ifas.ufl.edu/plants/edibles/vegetables/peppers.html

Meet the author: Mattias is an experienced gardener spending most of his free time on his knees among herbs, plants, and garden vegetables. For the past two years, he has been sharing gardening projects and how-to tutorials on the NordicLavender website and YouTube channel.