Potato plant has got relatively high demand for water usage in the course of its growth compared to most plants. The peak of its water requirement is during the tuber bulking stage normally six weeks after emergence). During this stage, the plant demand high amounts of water to produce food for itself and for storage. Therefore, the high water required during this stage is critical for high yield of tubers. Water availability around the root zone during tuber initiation helps to minimize the common scab (hardening of young skin which results in cracks) from developing in tubers. However, excess amount of water can encourage attack by powdery scab and lenticel growth which can lower potato yield. Excess water can also lead to overgrowth of vegetative canopy which provide hideouts for pests such as aphids. Therefore, too much or too little water reduces the potato yield. The optimum amount of water required by potato plant varies depending on the variety, stage of growth and prevailing weather conditions.