Adequate irrigation design, good irrigation management and scheduling have long been recognised as keys to increasing vegetable production on a sustainable basis. Scheduling irrigation according to crop water needs minimises the chances of under or over watering. Consequently, there is less crop failure and leaching of fertilisers beyond the root-zone, and more profit for growers. This approach underpins the long-term viability of an efficient and sustainable production system for the irrigated vegetable industry. Weather data has been used for estimating crop water requirements for many years, and is a handy management tool when it is used in conjunction with scheduling methods. The Moisture Accounting Method involves steps to estimate soil moisture content by using weather data and is based on soil water balance.