Dry patch (water-repellent soil)
Patches where water runs off or beads on the surface instead of soaking in, so the grass dries out even after watering. Common on sandy soils.
Also called: Hydrophobic soil, Water repellent soil, Non-wetting soil, Dry patches
Short answer
Dry patch is when water beads or runs off instead of soaking in, so patches of lawn dry out even after watering. It is common on sandy soils that have turned water-repellent, and on lawns watered unevenly. Check sprinkler coverage with a catch-cup test, test the soil with a few drops of water, and use a wetting agent if water won't soak in.
Overview
Dry patches are one of the most common summer lawn problems, especially on sandy soil. When some soils dry out, a waxy or oily coating on the sand grains starts to repel water. Water then beads on top or runs off, and the patch gets drier every time.
Before reaching for a product, work out the cause. Water repellence, poor sprinkler coverage, compaction and lawn grubs can all look the same from above, and the fix for each is different.
Symptoms
- Brown, dry patches that stay dry after rain or watering
- Water that beads or runs off instead of soaking in
- Soil under the patch that is dry a few centimetres down
Possible causes
- Water-repellent soil: sand grains with an oily or waxy coating push water away
- Uneven sprinkler coverage
- Compacted soil that water can't get into
- Lawn grubs eating roots: lift a piece of turf to check
- Fairy rings, which can make soil water-repellent in a ring
Work out the cause
Pour a cup of water on the dry patch. If it beads or sits on the surface instead of soaking in, the soil is water-repellent.
Push a screwdriver or trowel into the patch after watering. If the soil is dry a few centimetres down, water isn't getting in.
Do a catch-cup test to see whether your sprinklers are reaching the patch.
Lift a piece of turf at the edge to rule out lawn grubs.
How to fix it
- Apply a wetting agent at the label rate and water it in. Water Corporation suggests applying it several times a year on WA sands.
- Fix sprinkler coverage first if the catch-cup test shows the patch gets less water.
- Core aerate compacted areas so water can get in.
- Water deeply and less often once water is soaking in again.
Popular questions about dry patch (water-repellent soil)
Guides
- application guideHow to apply lawn grub and armyworm treatments
- application guideHow to apply a lawn wetting agent
- irrigation guideThe catch-cup test: measure what your sprinklers actually put out
- GuideThe complete guide to buffalo lawns
- irrigation guideHow much water does a lawn need?
- irrigation guideHydrophobic soil: why water won't soak in, and how to fix it
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Sources
- Bring your brown lawn back to life, Water Corporation (Western Australia)Water-repellent sands, wetting agents, uneven watering, catch cups and aeration. Accessed 4 October 2026.