Weekly irrigation needed after rain and system efficiency.
Rain is subtracted from the crop's evapotranspiration, then the deficit is scaled up for system losses. Scheduling against actual evapotranspiration instead of a fixed timer saves water and avoids root stress.
Irrigation Scheduling
Apply = (crop use - rain) / efficiency; gallons = inches/12 x area x 7.48
Apply = (crop use - rain) / efficiency; gallons = inches/12 x area x 7.48 Rain is subtracted from the crop's evapotranspiration, then the deficit is scaled up for system losses.
Scheduling against actual evapotranspiration instead of a fixed timer saves water and avoids root stress.
This calculator takes 4 inputs: Crop water use, Rain received, System efficiency, Watered area. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.