Pepper needs some basic nutrients in the growth process. If one nutrition elements lacks, it will greatly affect the plant growth and yield, especially ferrous deficiency (ferrous sulfate). Ferrous element not only can produce chlorophyll and fix nitrogen element but also promote respiration and photosynthesis in plants. There are some ways to help you identify pepper ferrous deficiency or other elements deficiency as bellow:
1. If the leaves of your pepper appear yellowing but major veins still keep green, that means ferrous deficiency; If both blades and major veins show yellow, that means nitrogen deficiency.
2. Judge nitrogen or ferrous deficiency by observing leaves lesions. When nitrogen lacks, the bottom leaves will gradually yellowing. When ferrous deficiency, the top new leaves show yellowing. If this not be treatment timely, symptoms will spread to all the plants.
3. Having excluded the possibility of nitrogen deficiency, test soil PH value to make sure the deficiency belongs to lack of magnesium or ferrous element.
4. Check the soil PH testing results, acidic or alkaline. If acidic, it shows your pepper is magnesium deficiency; if alkaline, more than 6.8, then it shows your pepper is ferrous deficiency.
5. Apply ferrous sulfate fertilizer as early as possible or lower soil PH value to control ferrous deficiency.