Green circles do not prove even coverage
A sprinkler can make a dramatic wet circle while the area between heads remains dry. Moving it farther to reduce the number of heads may look cheaper, but it removes the overlap that helps one sprinkler cover the weak outer edge of another. The lawn then tells the story through recurring dry patches, runoff and longer run times.
Head-to-head coverage means the throw from one correctly operating sprinkler reaches approximately to the neighbouring head as required by the chosen design pattern and product data. It is a starting principle, not a guarantee: pressure, wind, nozzle choice, spacing, obstacles and site shape still need to be tested.
For layout, hydraulics and commissioning together, explore Green Earth Concepts Irrigation Systems.
Uniformity begins with the boundary
Place conceptual heads at corners and changes in direction, then work inward using a recognised square, triangular or other suitable arrangement. Keep water on planted areas and away from walls, windows, paths, roads and neighbouring properties. Narrow strips may need a different device or a landscape redesign rather than full-circle sprinklers.
Use compatible bodies and matched nozzles within a zone as specified by the manufacturer. Working pressure at the head must support the selected nozzle without collapse or excessive misting. Wind may require shorter spacing, different scheduling or another method. Trees, shrubs, furniture and level changes can distort a pattern that looked perfect on paper.
Catch-can verification should be planned, not performed as a photo opportunity. Use identical straight-sided containers placed across a representative part of the pattern, avoid positions that create a trip or mower hazard, and run long enough to measure meaningful differences without causing runoff. Record wind and pressure. Compare the distribution of collected depths rather than relying only on the average: a good average can hide one repeatedly dry edge.
Uniform application is only half the result. Probe the soil after a suitable interval to see whether water entered the intended root zone or ran across a compacted surface. Correct blocked heads, pressure and layout faults before changing run time. Where infiltration is slower than application, cycle-and-soak scheduling or a different nozzle may help, but drainage, slope and soil condition still need attention.
Repeat the check after nozzle changes, major landscaping, pressure adjustments or seasonal growth around the heads. A commissioning result is a baseline, not permanent proof. Record the container layout and conditions so a later team can compare like with like.
Group lawn separately through hydrozoning, and use the commissioning checklist before accepting the finished zone.
Lay out and test the lawn zone
- 01
Map the irrigable boundary
Measure the lawn after excluding paths, beds, walls, play areas and any place that should remain dry. Mark slopes and prevailing wind.
- 02
Choose the appropriate sprinkler family
Use current product data for radius, arc, flow and pressure. Do not mix devices with incompatible application behaviour on one zone.
- 03
Place boundary heads first
Start at corners and shape changes so arcs can keep water inside the lawn. Use adjustable arcs only where their performance and maintenance are suitable.
- 04
Create head-to-head overlap
Position neighbouring heads according to the product and layout method so each supports the weaker edge of another pattern. Adjust for wind and irregular geometry.
- 05
Check zone demand
Sum nozzle flows and verify that the source and pipe network can maintain suitable working pressure. Split the area when demand or elevation makes one zone unreliable.
- 06
Install level and accessible
Set bodies so they operate without creating a trip or mower hazard, remain serviceable and are not blocked by mature vegetation.
- 07
Commission every arc
Flush, inspect rotation or spray, correct leaks, verify pressure, set arcs and check that no water is thrown onto prohibited surfaces.
- 08
Run a catch-can check
Place identical containers in a representative grid, run under calm comparable conditions and compare collected depth. Use the pattern to diagnose layout or nozzle issues before simply increasing run time.
Dry-patch troubleshooting
| Pattern | Possible cause | First verification |
|---|---|---|
| Dry area midway between heads | Spacing, radius or working pressure | Measure actual throw and pressure under operation |
| One wedge stays dry | Arc, blocked nozzle or obstruction | Inspect that head and its view of the area |
| Downwind edge is dry | Wind distortion | Observe in calmer and normal windy periods |
| Low area is wet | Runoff, drainage or low-head leakage | Check slope, application rate and valve closure |
| Fine mist across zone | Excess pressure or wrong nozzle | Compare working pressure with product requirement |
Sign-off checks
- Heads and arcs respect every no-spray boundary.
- Spacing and nozzle selection follow reviewed product data.
- Working pressure is checked with the complete zone running.
- No head is blocked, tilted, buried or unsafe.
- Catch-can results show no unexplained persistent gap.
- Runoff is prevented through scheduling or design correction.
Overlap first, verify second
- Design from boundaries and no-spray areas inward.
- Support the outer edge of each pattern with planned overlap.
- Match nozzles and confirm pressure under operation.
- Use catch cans and root-zone observations before changing schedules.
Correct dry patches at the design level
Green Earth Concepts can measure the lawn, pressure and source capacity, review boundaries and wind, and commission a zone for usable coverage rather than visible spray. The assessment can identify whether correction, rezoning or a different method is the practical answer.
Sprinkler-layout questions
Does head-to-head mean every lawn will be perfectly uniform?
No. It is an important layout principle, but actual performance also depends on working pressure, nozzle compatibility, wind, arcs, obstacles, installation and maintenance. Verify the finished zone.
Can I fix dry patches by running longer?
Longer operation may over-water the better-covered areas while the gap remains. Diagnose spacing, pressure, nozzle, obstruction and soil infiltration first.
Should sprinklers run in windy conditions?
Wind distorts patterns and increases drift. Schedule for suitable conditions where practical, but also design for the site's normal exposure rather than assuming every day will be calm.
The space between sprinklers is the real test
A lawn should not depend on over-watering one area to rescue another. Build deliberate overlap, protect boundaries and verify the finished pattern under real pressure. Uniformity is measured performance, not a drawing of circles.