The cucumber leaves turning yellow of a plant are its solar panels, absorbing sunlight and turning it into sugars to feed the entire plant. When the leaves start turning yellow, it means that your plants are struggling to make food. This discoloration is called chlorosis, and it’s a sign that the plant needs more nutrients to thrive. The good news is that there are several things you can do to prevent or fix cucumber leaves turning yellow.

The first step is to perform a visual inspection of the leaves. You may be able to spot pests such as aphids, potato leafhoppers, and cucumber beetles that suck the sap out of the leaves and cause them to turn yellow. Cucumber plants also suffer from several diseases that can turn the leaves yellow or brown. Cucumber wilt, caused by six species of Verticillium fungus, is one example. Downy mildew, caused by Pseudoperonospora Cubensis, is another. The fungus causes light green to yellow angular spots on the leaves, which then turn brown.

Troubleshooting Yellowing Cucumber Leaves: Causes and Solutions

Other common reasons for cucumber leaves turning yellow include nutrient deficiencies and stress from environmental conditions. A lack of nitrogen may be the culprit, and you can fix it by adding some compost or coffee grounds to the soil. If your cucumbers are lacking in phosphorus, look for organic fertilizers that contain this vital nutrient. A lack of iron may also cause your cucumbers to turn yellow between the veins, and this can be remedied by spraying with a solution of zinc sulfate or organic kelp.

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