Guide · 6 min read
Cycle-soak scheduling: stop paying for runoff
Most sprinkler zones apply water faster than most soils can absorb it. Once the surface saturates, additional minutes stop irrigating and start washing water down the gutter. Cycle-soak programming splits the total runtime into several short cycles separated by soak intervals, so each cycle stays within what the soil can take and the pauses let it drain before the next round.
The arithmetic needs only two numbers you already have after an audit: the zone's measured precipitation rate and a working intake rate for the soil.
Sizing the longest safe cycle
The longest cycle before runoff begins is the soil intake rate divided by the precipitation rate, converted to minutes. A loam absorbing at 0.45 inches per hour under a spray zone applying 1.5 inches per hour saturates in 0.3 of an hour, so cycles are capped near 18 minutes. On clay under the same heads the cap drops to roughly 8 minutes.
Slope tightens the cap further: on grades, water starts moving before the soil is saturated, so auditors commonly shorten cycles well below the flat-ground figure and watch the first program run for surface movement.
Building the program
Divide the weekly runtime by the number of watering days for a per-day total, then split that total into cycles no longer than the cap. The number of cycles you need per day must fit the controller's programmed start times: three 13-minute cycles need three start times spaced far enough apart to soak between them.
Soak intervals of roughly 30 to 60 minutes between cycles are common practice on turf; heavier soils and slopes benefit from the longer end. The Irrigaudit schedule view performs this split automatically and warns when the soil needs more cycles than the controller has start times.
Seasonal adjust and the weekly budget
Controllers apply a seasonal adjust percentage on top of programmed minutes. Program the peak-season runtime, then dial the percentage down in spring and fall instead of rewriting every station. Irrigaudit applies your seasonal adjust to the recommended runtime before splitting cycles, so the program table shows what the controller will actually run.
Local ET data, effective rainfall, and watering-day restrictions all still apply. A catch-can audit tells you how the system performs; it does not know this week's weather.
Frequently asked questions
How long can each irrigation cycle run before runoff starts?
Divide the soil intake rate by the zone's precipitation rate and convert to minutes. Example: 0.45 inches per hour intake under 1.5 inches per hour application gives 0.3 hours, about 18 minutes per cycle on flat ground. Slopes need shorter cycles.
How long should the soak interval between cycles be?
Common practice on turf is roughly 30 to 60 minutes, longer on clay and slopes. The interval needs to be long enough for surface water to infiltrate before the next cycle begins.
What if my controller does not have enough start times for the cycles I need?
Either add start times, spread the runtime over more watering days, or accept some runoff risk. The Irrigaudit schedule view flags exactly this condition, showing the cycles the soil needs against the start times programmed.
Does seasonal adjust change the cycle split?
Yes. The adjust percentage scales total minutes, which changes how many capped cycles are needed per day. Compute the split from the adjusted runtime, which is what Irrigaudit does.