Micro-Sprinkler Coverage & No Dry Gaps
Lays out spacing
Enter wetted diameter, overlap and field area to get the sprinkler spacing, the coverage per sprinkler and the number of micro-sprinklers needed for full wetting.
Lay out micro-sprinklers
Next: space heads at 4 m in a square grid and order 253 micro-sprinklers for 0.4 ha.
Square vs triangular layout, wind, and emitter model change effective overlap; size your pump and submain to the total head flow.
Micro-sprinkler coverage — key facts
- Spacing
- = wetted diameter × (1 − overlap)
- Number
- = area ÷ coverage per sprinkler
- Good overlap
- ≈ 20–30%
- Wets
- A circle around each tree
- Too little overlap
- Dry gaps between circles
- Check pressure
- Sets the real wetted diameter
- Suits
- Orchards & sandy soils
- Privacy
- Runs in your browser; nothing uploaded
Overlap the circles and the dry gaps disappear
A micro-sprinkler wets a neat circle of soil around each tree, but a single circle waters heavily at the centre and thinly at the rim. Space the sprinklers exactly one diameter apart and the seams between circles stay dry; pull them closer so the circles overlap by a fifth to a third and the whole block wets evenly. The spacing that does this is simply the wetted diameter reduced by the overlap you choose.
This tool turns your wetted diameter and overlap into a spacing, the coverage each sprinkler serves, and the total number of micro-sprinklers for your area — the numbers you need to buy fittings and lay the lines. Pair it with the Sprinkler System, Rain Gun, Nozzle Discharge and Drip Emitter Spacing tools to design the full block.
Kill the dry gaps
Overlap evens out water between circles.
Right spacing
Diameter minus overlap sets the layout.
Know the count
Area ÷ coverage gives sprinklers to buy.
Plan the block
Coverage per sprinkler sizes the system.
Frequently Asked Questions
What does a micro-sprinkler wet?+
Each micro-sprinkler throws water in a circle around itself, wetting a patch of soil under and around the tree. The diameter of that circle — the wetted diameter — depends on the nozzle, pressure and the spinner or jet type. Trees within the wetted circle get watered; gaps between circles stay dry unless the layout overlaps them.
How is the spacing calculated?+
With an overlap allowance, the spacing between sprinklers is the wetted diameter × (1 − overlap). So a 4 m wetted diameter with a 25% overlap gives 4 × 0.75 = 3 m spacing. Pulling the sprinklers closer than the bare diameter overlaps the circles and removes the dry gaps.
Why is overlap important?+
A single sprinkler waters most near the centre and least at the rim, so two circles that just touch leave a poorly wetted seam between them. Overlapping the circles by 20–30% evens out the application and ensures every tree, including those between sprinklers, gets enough water.
How is the number of sprinklers found?+
The number is the field area ÷ the coverage per sprinkler, where coverage per sprinkler is the effective area each one serves after the overlap-reduced spacing. This tool computes the per-sprinkler coverage and divides the total area by it to give the count you need to buy and install.
What is coverage per sprinkler?+
It's the effective ground area one micro-sprinkler is responsible for, based on its overlap-adjusted spacing. Because overlap reduces spacing, each sprinkler covers a little less than its full wetted circle — that smaller, reliable area is what you divide the field by to size the system.
What wetted diameter should I use?+
Use the figure from the sprinkler's catalogue at your operating pressure, or measure it in the field by running one sprinkler and marking where the spray reaches. Lower pressure and clogged nozzles shrink the wetted diameter, so check it under real conditions rather than trusting the spec alone.
How does this differ from drip spacing?+
Drip emitters wet a small bulb at each point, so spacing follows the wetting pattern in the soil. Micro-sprinklers wet a broad surface circle, so spacing follows the spray geometry and overlap. Micro-sprinklers suit orchards and sandy soils where a wider wetted area helps; drip suits row crops and water-scarce settings.
Can I match one sprinkler per tree?+
Often yes — in orchards a single micro-sprinkler is placed at or near each tree so its circle wets that tree's root zone. In that case spacing follows the tree spacing, and you check that the wetted diameter covers the active root zone with the overlap you want between neighbouring trees.
Does slope or wind affect coverage?+
Yes. Wind distorts the spray circle and pushes water downwind, while slope shifts the wetted patch downhill. On windy or sloping sites reduce spacing (increase overlap) and consider lower-trajectory micro-jets so the pattern stays uniform across the block.