This page is experimental - use at your own risk.
What is this?
This page attempts to give a guideline for the amount of irrigation required for turf and plants, based on
the amount of rain within the past seven days, and the computed evapo-transpiration (ET), based on the
amount of sun hours, sun intensity, and humidity for the past week. These two variables are rolling values
and are updated each day at midnight. If the value of "Total Run Time" is zero or negative, then no irrigation
is needed at this time, and "Run Irrigation" will be zero minutes. You can use this information as a guideline
for setting the watering system timer schedule.
The information used to make these calculations is derived from data available from the
Irrigation Technology
Center at Texas A&M University. There are many, many variables involed in this calculation of a watering
schedule, such as how much the plant's own shade plays a factor, soil condition (pristine vs. poor), and the
current forecast (this page does not look ahead and adjust watering schedules based on predicted rain; it
only uses past rain as an input), etc., but this simple version does not take them all into account, so, again,
use this as a guideline only.
Assumptions:
- For turf: turf is in full sun, sprinklers deliver the equivalent of 0.5" of rain/hour.
- For plants: the water application system is drip and delivers the equivalent of 0.25" of rain/hour.
- The watering schedule is: one day a week for turf during the autumn/winter (as generally very little
water is needed and it's better to deep water turf) and two days per week for plants.