On days with extreme conditions, the upper rate may need to be increased. The figures assume no rainfall. If rainfall exceeds the amount of irrigation required, do not apply water. If rainfall does not exceed the irrigation required, subtract the amount of rainfall from the irrigation required and apply this amount of water. Established growers can use the Tables to check whether they are applying approximately the correct amount of water.
New growers can use the rates as a starting point to determine their irrigation program.
These rates do not include watering for frost or dust control or for protection from sand blasting. They assume an irrigation system with good watering uniformity. If water application is uneven, increase the rates to deliver sufficient water to the drier areas of the garden. Many irrigation systems do not deliver water uniformly. This may be due to sprinklers being spaced too far apart, low water pressure or worn nozzles.