Short answer: Brown patches usually come from one of a handful of causes — drought, dog urine, scalping (mowing too short), fungal disease such as red thread, spilt fertiliser or buried debris, or grubs (leatherjackets and chafers) eating the roots. You can often tell them apart by the shape and pattern of the browning. Most patches recover once you fix the cause and, if needed, overseed the bare area.
The tricky part is that very different problems can look similar from a distance. The clue is usually in the pattern — scattered, circular, edge-only, or in the exact spots your dog visits.
Common causes and how to spot them
| Cause | What it looks like | Fix |
|---|---|---|
| Drought | Large, irregular straw-coloured areas in dry spells, worst over sandy soil or tree roots | Water deeply; it usually greens up when rain returns |
| Dog urine | Small round brown spots, often with a darker green ring, where a dog toilets | Dilute with water immediately; rinse the area; reseed if needed |
| Scalping | Brown wherever the ground is high — bumps, edges, slopes | Raise the mower height; level bad bumps |
| Fungal disease (e.g. red thread) | Patches with pink/red threads or tan patches in warm, damp weather | Improve airflow and feeding; avoid overwatering |
| Spilt fertiliser / buried debris | Sharp-edged dead patches where product was spilt or rubble sits below | Flush spills with water; remove buried debris and reseed |
| Grubs (leatherjackets, chafers) | Patches that lift like a rug; birds or badgers digging | Encourage strong roots; treat grubs if severe |
How to diagnose your patch
Work through these questions:
- Has it been hot and dry? Broad, straw-coloured browning that follows a dry spell is almost always drought — especially over sandy soil or tree roots. See how often to water your lawn.
- Are the patches small and round, in a dog's favourite spots? That's urine scorch.
- Is the brown only on high points, bumps and edges? That's scalping from mowing too short — raise your mowing height.
- Do you see coloured threads or it's been warm and humid? Suspect a fungal disease like red thread, which often follows underfeeding.
- Does the turf lift away easily, or are birds pecking at it? Grubs are eating the roots underneath.
How to fix and prevent brown patches
Once you know the cause, the fix follows:
- Remove the cause — water in drought, dilute urine spots, raise the mower, flush spills, or treat grubs.
- Rake out the dead grass to expose the soil.
- Overseed the bare area so grass fills it back in — see how to overseed a lawn.
- Feed and water appropriately to help recovery and prevent a repeat. A well-fed, deep-rooted lawn resists most patch problems.
Not sure which cause you're looking at? YardIQ can assess a photo of the affected area and suggest the most likely reason and fix, then add the repair to your plan.
Frequently asked questions
Will brown patches in my lawn grow back?
Often, yes. Drought-browned grass is usually dormant, not dead, and greens up when rain returns. Patches killed by urine, spills or disease may not recover on their own — rake out the dead grass and overseed the bare area to fill it in.
Why does my dog's urine cause brown spots on the lawn?
Dog urine is high in nitrogen and salts, which scorch the grass in a concentrated spot — often leaving a small brown patch ringed by darker, over-fertilised green. Rinse the area with water soon after, and reseed spots that don't recover.
What are the round brown patches in my lawn?
Small, neat round patches are often dog urine scorch or a fungal disease. Look for a darker green ring (urine) or coloured threads and a link to warm, humid weather (disease such as red thread). The shape and any threads help you tell them apart.
How do I stop brown patches coming back?
Keep the lawn deep-rooted and healthy: water deeply but infrequently, mow high (never removing more than a third of the blade), feed in season, and improve airflow and drainage. A strong lawn resists drought, disease and grubs far better than a stressed one.