While it can be disheartening to see pepper seedlings yellow leaves leaves, there are a few steps you can take to correct the problem and keep your plants healthy. First, you should do a soil test to see what nutrients are deficient in your garden bed or container. If it turns out you have a nitrogen deficiency, you will need to add fertilizer. You can use a natural, organic fertilizer with a good balance of nitrogen like manure tea or a commercial product like Fox Farm’s trio fertilizer which is designed to work together to provide all of the essential macronutrients (nitrogen, phosphorus and potassium) for your plants. Fertilizing won’t turn your pepper plant leaves back to green, but it will help to fuel foliage growth and stop the yellowing process.
Troubleshooting Yellow Leaves on Pepper Seedlings: Common Causes and Solutions
Other possible causes of yellowing pepper plant leaves are water stress and disease. If your pepper plants are suffering from a disease like bacterial leaf spot, wilt or phytophthora blight you will likely notice other symptoms along with the yellowing leaves such as brown spots on the leaves or a mushy or rotten appearance of the pepper plant. If this is the case, you will need to rip out the plant and start fresh.
Also, if your pepper plant is yellowing due to fungus, it’s important to use a mild homemade fungicide to control the disease without harming beneficial insects or other crops in your garden. Fungicides such as neem oil and insecticidal soaps will work to kill the fungus and prevent it from spreading.