A controller tells you time, not water depth. A catch-cup test shows how much water reaches the lawn and whether the coverage is even enough to trust your schedule.
Set up a fair test
Place identical straight-sided containers across the zone, including the edges and any area that regularly looks dry. Keep cups clear of spray-blocking plants and run the zone long enough to collect a measurable amount.
Calculate the application rate
Measure every cup, add the depths, and divide by the number of cups. That average is the depth applied during the test runtime. Scale it proportionally to estimate the runtime for your target depth.
Example only: if a 15-minute test averages 0.25 inch, the measured rate is about 1 inch per hour.
Use variation to find problems
The average sets runtime; the spread between cups reveals uniformity. Very low cups near healthy readings often point to alignment, nozzle, or obstruction problems—not a need to water the entire zone longer.
Field kit
What I use
- Catch cups
- Rain gauge
- Tape measure
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