Why Green Pepper Plants Turn Yellow

When the leaves of your green pepper (Capsicum) plants start to turn yellow, it doesn’t mean that the peppers also will turn yellow. The yellowing leaves indicate malnutrition, among other causes, and as a gardener, you must remedy the situation if your harvest is to be successful. Testing the soil, watering and not soaking the plants, and cooler weather contribute to the health of the peppers. Planting when the ground is not warm enough also causes leaves to turn yellow. While the yellow leaves will not turn green again, you can monitor and correct the problem to save the peppers from damage.


Green peppers are green peppers. They won’t turn into red or yellow peppers, but when their leaves start turning yellow, the causes should be diagnosed immediately to avoid the destruction of the crop.

Diagnosing Yellow Leaves on Pepper Plants

If the leaves on the pepper plant are turning yellow from the base of the plant and moving upward through the stalk, they have a malnutrition problem. The plant receives its potassium, nitrogen and phosphorus from the soil, and as it invades the leaves, the deficiency moves with it. Gardening Chores mentions that the leaves are the first to react to an adverse situation.

To grow into healthy mature plants, peppers need to get nitrogen from the soil. Without adequate nitrogen, the larger green leaves on the pepper plant will start to turn yellow as the nitrogen deficiency moves from the bottom of the stalk upward. The older leaves, deprived of nitrogen, turn yellow and fall off, while the younger, upper leaves take what they can get. Fertilizing weekly with nitrogen-rich slow-release granular fertilizer helps remedy the problem. Use a 5-5-5 formula fertilizer.

Water Stress Causes Yellowing of Peppers

Too much or too little water affects the leaves of the pepper plant, and as the indicator of all things good and bad in the growing pepper plant, yellow leaves mean a problem. Pepper plants do better with too little water than too much. They don’t like soggy roots, which can cause root rot. The soil must drain well and not be so compacted that it won't allow moisture to soak in. The soil also must be loose enough to allow oxygen to pass through it to feed the plant.

Underwatering, which causes less of a problem, is easily corrected. Just don’t go to extremes. If you have a moisture indicator, use it. If not, stick your finger into the soil to a depth of a few inches. If it comes out moist, the plant has received enough water. If it comes out dry, create a watering schedule, especially if the weather turns hot and dry.

Extreme Temperatures Bring on Yellow Leaves

With climate change affecting the country, extreme temperatures may affect your pepper crop. Peppers are a warm-weather crop, and if the temperatures fall below 50 degrees Fahrenheit, consider it a warning that your plants may experience yellowing pepper leaves. If possible, cover the plants at night to keep them warm. If they're in a container, bring it indoors when the temperature drops. The cooler temperature is an indicator to the plant that it’s time to hibernate, even if the peppers haven’t reached maturity.

Pepper Geek writes that a temperature below 40 degrees Fahrenheit will have an immediate effect on the leaves and cause them to drop. Anything below 32 F will kill the plant. You can diagnose a cold-weather condition by looking at the yellow leaves. If they're scattered throughout the plant, weather conditions probably caused them to turn yellow.