What causes pea leaves to turn yellow?

Several factors can cause pea leaves to turn yellow. Here are some common causes:

- Nitrogen Deficiency:

Nitrogen deficiency is one of the most common reasons for yellowing of pea leaves. Nitrogen is essential for chlorophyll production and overall plant growth. When peas lack sufficient nitrogen, the oldest leaves start turning yellow as the plant reallocates nitrogen from old to new leaves.

- Lack of Sunlight:

Peas require adequate sunlight to produce chlorophyll and perform photosynthesis. Insufficient light can lead to yellowing of leaves, especially the older ones.

- Over-watering:

Excess water can cause root rot, leading to yellowing and wilting of leaves. Waterlogged soil restricts oxygen supply to the roots hindering nutrient absorption.

- Pests and Diseases:

Certain pests, like aphids and spider mites, feed on the sap of pea leaves, causing yellow spots and reduced growth. Fungal diseases like powdery mildew and downy mildew can also lead to yellowing and eventual defoliation.

- Nutrient Imbalances:

Deficiency or imbalance of other nutrients, such as phosphorus, potassium, iron, or magnesium, can also cause pea leaves to turn yellow.

- Natural Aging:

As pea plants age, the older leaves may turn yellow and eventually drop off as the plant focuses its energy on newer growth.

- Iron Deficiency:

This is also a relatively common cause of yellow leaves in peas. Iron is an important micronutrient involved in chlorophyll production. Without sufficient iron, plants can develop yellow leaves even if they have enough nitrogen.