You should not allow cucumbers to turn yellow. If you encounter a yellow cucumber, it’s usually over ripe. When cucumbers become over ripe, their green coloring produced from chlorophyll begins to fade, resulting in a yellowing pigment. Cucumbers become bitter with size and yellow cucumbers are generally not fit for consumption.

A yellow cucumber can also be the result of a virus, too much water, or a nutrient imbalance. In some instance, yellow cucumbers are derived from planting a yellow-fleshed cultivar, such as the lemon cucumber, which is a small, lemon-shaped, pale yellow variety.